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AuthorTitleYearJournal/ProceedingsReftypeDOI/URL
Amalvict, M., Hinderer, J. and Rózsa, S. Crustal vertical motion along a profile crossing the Rhine graben from the Vosges to the Black Forest Mountains: Results from absolute gravity, GPS and levelling observations 2006 Journal of Geodynamics
Vol. 41(1-3), pp. 358-368
article DOI
Abstract: The Rhine plain is oriented north-south and limited by the Vosges
Mountains (France) to the West and the Black Forest Mountains
(Germany) to the East. The present-day tectonic evolution of
this system is not well known and many questions are still
pending: is the graben subsiding? Are the mountains uplifting?
What is the relative behaviour of the three different geological
components? In attempting to answer these questions, we compare
for the first time in this region time series of absolute
gravity (AG) measurements to the available GPS observations at
three sites along a profile crossing the Rhine graben. Our
reference station is the gravimetric observatory near Strasbourg
(J9), located in the Rhine plain where AG measurements are
performed regularly since 1997 and where superconducting
gravimeter (SG) observations are available almost continuously
for 17 years. The secondary sites are the Welschbruch station in
the Vosges Mountains where six AG measurements have been
conducted since 1997 and the Black Forest Observatory (BFO)
where three AG measurements are available. GPS permanent
receivers are collocated at the Strasbourg-J9 site since 1999,
at the Welschbruch station since 2000, and at BFO since 2002.
Levelling data are only available in the BFO region. We compare
the long term content of two types of geodetic measurements with
special emphasis on the trend despite the limited duration of
our data sets. Assuming that the gravity changes are linear in
time, we obtain ġ=1.9\pm0.2
\muGal/yr at Strasbourg-J9,
ġ=-0.96\pm0.2 \muGal/yr at
Welschbruch site and ġ=2.5\pm0.5
\muGal/yr at BFO. The trends according to GPS
observations are, respectively: -1.51 \pm 0.07
and -0.74 \pm 0.10 mm/yr at Strasbourg-J9 and
Welschbruch site, respectively; there is no GPS result available
at BFO. The AG results for BFO are very questionable, as well as
the GPS observations at the Welschbruch station. Nonetheless,
Strasbourg-J9 and Welschbruch AG measurements lead to subsidence
and uplift, respectively, which are expected results in
agreement with GPS at Strasbourg-J9.
BibTeX:
@article{2006JGeo...41..358A,
author = {Amalvict, M. and Hinderer, J. and Rózsa, S.},
title = {Crustal vertical motion along a profile crossing the Rhine graben from the Vosges to the Black Forest Mountains: Results from absolute gravity, GPS and levelling observations},
journal = {Journal of Geodynamics},
year = {2006},
volume = {41},
number = {1-3},
pages = {358-368},
doi = {https://doi.org/10.1016/j.jog.2005.08.036}
}

Bennett, R.A. and Hreinsdóttir, S. Constraints on vertical crustal motion for long baselines in the central Mediterranean region using continuous GPS 2007 Earth and Planetary Science Letters
Vol. 257(3-4), pp. 419-434
article DOI
Abstract: GPS-determination of vertical crustal velocity relative to a globally
defined reference frame is limited by the accuracy of the
reference frame origin and scale. However, the precision of
relative vertical rates at regional-distance scales remains
largely unexplored. We investigated the precision of regional-
scale vertical velocity estimates using data from seven
continuously operating GPS stations located in the central
Mediterranean. The stations form a network of aperture
\sim 500 km and each has been in operation for at
least 5 yr. We used published constraints on recent crustal
uplift inferred from late Quaternary shoreline data to aid in
the definition of a local vertical reference frame for GPS rates
to facilitate an assessment of GPS vertical precision. We
explored different methods of defining the local reference
frame. The simplest method involves the estimation of a single
scalar translation parameter. Adjusting the reference frame by
this simple method yields agreement between CGPS and Holocene
shoreline data sets at the level of 0.2 to 0.4 mm/yr. Relative
rates determined using CGPS are also consistent with tide gauge
records and sea level determined by satellite altimetry at the
level of about 0.2 mm/yr. These results suggest that regional-
scale relative velocity precision well below the mm/yr-level is
now possible using continuous GPS.
BibTeX:
@article{2007E&PSL.257..419B,
author = {Bennett, Richard A. and Hreinsdóttir, Sigrún},
title = {Constraints on vertical crustal motion for long baselines in the central Mediterranean region using continuous GPS},
journal = {Earth and Planetary Science Letters},
year = {2007},
volume = {257},
number = {3-4},
pages = {419-434},
doi = {https://doi.org/10.1016/j.epsl.2007.03.008}
}

Cushing, E.M., Bellier, O., Nechtschein, S., Sébrier, M., Lomax, A., Volant, P., Dervin, P., Guignard, P. and Bove, L. A multidisciplinary study of a slow-slipping fault for seismic hazard assessment: the example of the Middle Durance Fault (SE France) 2008 Geophysical Journal International
Vol. 172(3), pp. 1163-1178
article DOI
Abstract: Assessing seismic hazard in continental interiors is difficult because
these regions are characterized by low strain rates and may be
struck by infrequent destructive earthquakes. In this paper, we
provide an example showing that interpretations of seismic cross
sections combined with other kinds of studies such as analysis
of microseismicity allow the whole seismogenic source area to be
imaged in this type of region. The Middle Durance Fault (MDF) is
an 80-km-long fault system located southeastern France that has
a moderate but regular seismicity and some palaeoseismic
evidence for larger events. It behaves as an oblique ramp with a
left-lateral-reverse fault slip and has a low strain rate. MDF
is one of the rare slow active fault system monitored by a
dedicated dense velocimetric short period network. This study
showed a fault system segmented in map and cross section views
which consists of staircase basement faults topped by listric
faults ramping off Triassic evaporitic beds. Seismic sections
allowed the construction of a 3-D structural model used for
accurate location of microseismicity. Southern part of MDF is
mainly active in the sedimentary cover. In its northern part and
in Alpine foreland, seismicity deeper than 8 km was also
recorded meaning active faults within the crust cannot be
excluded. Seismogenic potential of MDF was roughly assessed.
Resulting source sizes and estimated slip rates imply that the
magnitude upper limit ranges from 6.0 to 6.5 with a return
period of a few thousand years. The present study shows that the
coupling between 3-D fault geometry imaging and accurate
location of microseismicity provides a robust approach to
analyse active fault sources and consequently a more refined
seismic hazard assessment.
BibTeX:
@article{2008GeoJI.172.1163C,
author = {Cushing, E. M. and Bellier, O. and Nechtschein, S. and Sébrier, M. and Lomax, A. and Volant, Ph. and Dervin, P. and Guignard, P. and Bove, L.},
title = {A multidisciplinary study of a slow-slipping fault for seismic hazard assessment: the example of the Middle Durance Fault (SE France)},
journal = {Geophysical Journal International},
year = {2008},
volume = {172},
number = {3},
pages = {1163-1178},
doi = {https://doi.org/10.1111/j.1365-246X.2007.03683.x}
}

D'Agostino, N., Avallone, A., Cheloni, D., D'Anastasio, E., Mantenuto, S. and Selvaggi, G. Active tectonics of the Adriatic region from GPS and earthquake slip vectors 2008 Journal of Geophysical Research (Solid Earth)
Vol. 113(B12), pp. B12413
article DOI
Abstract: To investigate the kinematics of the Adriatic region, we integrate
continuous and episodic GPS measurements with M_w gt 4.5
earthquake slip vectors selected from the Regional Centroid
Moment Tensor catalogue. Coherent motion of GPS sites in the Po
Valley, in Apulia, and in the Hyblean Plateau allows us to
estimate geodetically constrained angular velocities for these
regions. The predictions of the GPS-inferred angular velocities
are compared with the earthquake slip vectors, showing that the
seismically expressed deformation at the microplate boundaries
is consistent with the observed geodetic motion. The remarkable
consistency between geodetic, seismological, and geological
evidence of active tectonics suggests that active deformation in
the central Adriatic is controlled by the relative motion
between the Adria and Apulia microplates. The microplates'
angular rotation rates are then compared with the rotation rates
calculated with a simple block model supporting the hypotheses
(1) that Apulia forms a single microplate with the Ionian Sea
and possibly with the Hyblean region and (2) that Adria and
Apulia rotate in such a way as to accommodate the Eurasia-Nubia
relative motion. We suggest that the present-day microplate
configuration follows a recent fragmentation of the Adriatic
promontory that during the Neogene rigidly transferred the
Africa motion to the orogenic belts that now surround the
BibTeX:
@article{2008JGRB..11312413D,
author = {D'Agostino, N. and Avallone, A. and Cheloni, D. and D'Anastasio, E. and Mantenuto, S. and Selvaggi, G.},
title = {Active tectonics of the Adriatic region from GPS and earthquake slip vectors},
journal = {Journal of Geophysical Research (Solid Earth)},
year = {2008},
volume = {113},
number = {B12},
pages = {B12413},
doi = {https://doi.org/10.1029/2008JB005860}
}

Garcia, R. and Crespon, F. Radio tomography of the ionosphere: Analysis of an underdetermined, ill-posed inverse problem, and regional application 2008 Radio Science
Vol. 43(2), pp. RS2014
article DOI
Abstract: After analysing the forward and inverse problems of radio tomography, a
time varying three-dimensional imaging method of the ionosphere
from GPS slant TEC data is described and applied at regional
scale. Our approach is based on local basis parametrisation of
electron density, and constrained by NeQuick ionosphere model
and its spatial gradients. Our inversion scheme is fundamentally
different from the data assimilation approach because it is not
based on a physical ionosphere model. Preliminary results
obtained with European GPS receiver data validate the stability
of our method which is able to retrieve small-scale ionosphere
features in properly resolved volumes. Many improvements are
still possible on the algorithm, and a careful validation of
inverted models by independent data is still necessary. However,
our inversion algorithm is shown to improve the determination of
the small-scale features of a coarse a priori ionosphere model.
BibTeX:
@article{2008RaSc...43.2014G,
author = {Garcia, R. and Crespon, F.},
title = {Radio tomography of the ionosphere: Analysis of an underdetermined, ill-posed inverse problem, and regional application},
journal = {Radio Science},
year = {2008},
volume = {43},
number = {2},
pages = {RS2014},
doi = {https://doi.org/10.1029/2007RS003714}
}

Boniface, K., Ducrocq, V., Jaubert, G., Yan, X., Brousseau, P., Masson, F., Champollion, C., Chéry, J. and Doerflinger, E. Impact of high-resolution data assimilation of GPS zenith delay on Mediterranean heavy rainfall forecasting 2009 Annales Geophysicae
Vol. 27(7), pp. 2739-2753
article DOI
Abstract: Impact of GPS (Global Positioning System) data assimilation is assessed
here using a high-resolution numerical weather prediction system
at 2.5 km horizontal resolution. The Zenithal Tropospheric Delay
(ZTD) GPS data from mesoscale networks are assimilated with the
3DVAR AROME data assimilation scheme. Data from more than 280
stations over the model domain have been assimilated during
15-day long assimilation cycles prior each of the two studied
events. The results of these assimilation cycles show that the
assimilation of GPS ZTD with the AROME system performs well in
producing analyses closer to the ZTD observations in average.
Then the impacts of assimilating GPS data on the precipitation
forecast have been evaluated. For the first case, only the AROME
runs starting a few hours prior the triggering of the convective
system are able to simulate the convective precipitation. The
assimilation of GPS ZTD observations improves the simulation of
the spatial extent of the precipitation, but slightly
underestimates the heaviest precipitation in that case compared
with the experiment without GPS. The accuracy of the
precipitation forecast for the second case is much better. The
analyses from the control assimilation cycle provide already a
good description of the atmosphere state that cannot be further
improved by the assimilation of GPS observations. Only for the
latest day (22 November 2007), significant differences have been
found between the two parallel cycles. In that case, the
assimilation of GPS ZTD allows to improve the first 6 to 12 h of
the precipitation forecast.
BibTeX:
@article{2009AnGeo..27.2739B,
author = {Boniface, K. and Ducrocq, V. and Jaubert, G. and Yan, X. and Brousseau, P. and Masson, F. and Champollion, C. and Chéry, J. and Doerflinger, E.},
title = {Impact of high-resolution data assimilation of GPS zenith delay on Mediterranean heavy rainfall forecasting},
journal = {Annales Geophysicae},
year = {2009},
volume = {27},
number = {7},
pages = {2739-2753},
doi = {https://doi.org/10.5194/angeo-27-2739-2009}
}

Wöppelmann, G., Letetrel, C., Santamaria, A., Bouin, M.N., Collilieux, X., Altamimi, Z., Williams, S.D.P. and Miguez, B.M. Rates of sea-level change over the past century in a geocentric reference frame 2009 Geophysical Research Letter
Vol. 36(12), pp. L12607
article DOI
Abstract: The results from a carefully implemented GPS analysis, using a strategy
adapted to determine accurate vertical station velocities, are
presented. The stochastic properties of our globally distributed
GPS position time series were inferred, allowing the computation
of reliable velocity uncertainties. Most uncertainties were
several times smaller than the 1-3 mm/yr global sea level
change, and hence the vertical velocities could be applied to
correct the long tide gauge records for land motion. The sea
level trends obtained in the ITRF2005 reference frame are more
consistent than in the ITRF2000 or corrected for Glacial-
Isostatic Adjustment (GIA) model predictions, both on the global
and the regional scale, leading to a reconciled global rate of
geocentric sea level rise of 1.61 \pm 0.19mm/yr
over the past century in good agreement with the most recent
estimates.
BibTeX:
@article{2009GeoRL..3612607W,
author = {Wöppelmann, G. and Letetrel, C. and Santamaria, A. and Bouin, M. -N. and Collilieux, X. and Altamimi, Z. and Williams, S. D. P. and Miguez, B. Martin},
title = {Rates of sea-level change over the past century in a geocentric reference frame},
journal = {Geophysical Research Letter},
year = {2009},
volume = {36},
number = {12},
pages = {L12607},
doi = {https://doi.org/10.1029/2009GL038720}
}

Rosat, S., Boy, J.P., Ferhat, G., Hinderer, J., Amalvict, M., Gegout, P. and Luck, B. Analysis of a 10-year (1997-2007) record of time-varying gravity in Strasbourg using absolute and superconducting gravimeters: New results on the calibration and comparison with GPS height changes and hydrology 2009 Journal of Geodynamics
Vol. 48(3), pp. 360-365
article DOI
Abstract: This paper is devoted to a detailed investigation of a continuous record
spanning more than 10 years (1997-2007) of the Strasbourg
superconducting gravimeter (SG GWR C026). We show the results
from various scale factor experiments using parallel
registrations with an absolute gravimeter (AG FG5#206). These
results allow us to discuss the time stability of the
calibration of the SG. We also superimpose the AG and SG
measurements to infer the long-term instrumental drift behavior
of the SG but also the seasonal effects present at our station.
These long-term effects are discussed in terms of height changes
by using collocated GPS measurements (since 1999) and in terms
of hydrology (mainly with large scale hydrological models). The
collocated GPS height changes help in separating the gravity
variation due to the vertical motion of the station from the
variation due to the mass redistribution.
BibTeX:
@article{2009JGeo...48..360R,
author = {Rosat, S. and Boy, J. -P. and Ferhat, G. and Hinderer, J. and Amalvict, M. and Gegout, P. and Luck, B.},
title = {Analysis of a 10-year (1997-2007) record of time-varying gravity in Strasbourg using absolute and superconducting gravimeters: New results on the calibration and comparison with GPS height changes and hydrology},
journal = {Journal of Geodynamics},
year = {2009},
volume = {48},
number = {3},
pages = {360-365},
doi = {https://doi.org/10.1016/j.jog.2009.09.026}
}

Larroque, C., Delouis, B., Godel, B. and Nocquet, J.-M. Active deformation at the southwestern Alps-Ligurian basin junction (France-Italy boundary): Evidence for recent change from compression to extension in the Argentera massif 2009 Tectonophysics
Vol. 467(1), pp. 22-34
article DOI
Abstract: Several hundred earthquakes of small and moderate magnitude occur each
year at the southwestern Alps-Ligurian basin junction. In
addition, the historical seismicity data attests for earthquakes
of magnitude close to 6.5. Despite the seismic hazard and the
vulnerability of this region, the present-day driving mechanism
of deformation and the major structures accommodating these
deformations remain unclear. This littoral area presents a
strong topographic gradient from 3000 masl on the Argentera
alpine massif to 2500 m.u.s.l. in the Ligurian basin and a
strong structural inheritage resulting from 50 My geological
evolution combining different processes such as continental
collision and ocean basin opening. We present new results about
the kinematics of the Corsica-Sardinia continental block with
respect to the western alpine belt. From 7 years of continuous
GPS measurements we show that a small part of the Nubia-Eurasia
convergence is certainly transferred northward of the
Maghrebides deformation belts to the Corsica-Sardinia block. In
the southwesternmost Alps from Torino to the Mediterranean
coast, the baselines reveal differential motions of lengthening
between the Po plain and the Argentera and shortening between
the Argentera and the Ligurian domain. In a region where few
focal solutions are available we determine seven new focal
mechanisms located in the Argentera massif. These new data
underline a quaternary change from compression to extension in
that part of the western alpine belt. The focal mechanisms
calculated attest for extensional faulting at shallow level
between 1 and 11 km depth. We add 7 focal mechanisms from the
literature to calculate the stress tensor: a homogeneous
solution indicates a direction of extension broadly
perpendicular to the topographic axis culmination of the
Argentera. In contrast, the earthquakes recorded below 15 km at
the northwestern margin of the Po plain testify reverse faulting
and a compressional state of stress in the deep crust. Thus, we
point out that the stress field is vertically heterogeneous in
the crust of the Argentera area. The Ligurian domain is mainly
characterized by reverse and strike-slip faulting. The major
earthquakes are located in the northern margin and at the ocean-
continent transition. These earthquakes are assumed to result
from the reactivation, in a compressional state of stress, of
the structures formed during the Oligo-Miocene opening of the
Ligurian basin. Finally, we propose three hypotheses to explain
the current deformation at the Alps-Ligurian basin junction,
taking into account the far-field kinematics between the Nubia
and the Eurasia plates, the topographic gradient between the
Argentera massif and the Ligurian oceanic floor and the
distribution of the deformations.
BibTeX:
@article{2009Tectp.467...22L,
author = {Larroque, Christophe and Delouis, Bertrand and Godel, Bélinda and Nocquet, Jean-Mathieu},
title = {Active deformation at the southwestern Alps-Ligurian basin junction (France-Italy boundary): Evidence for recent change from compression to extension in the Argentera massif},
journal = {Tectonophysics},
year = {2009},
volume = {467},
number = {1},
pages = {22-34},
doi = {https://doi.org/10.1016/j.tecto.2008.12.013}
}

Renag Group RESIF-RENAG : The French GPS component of a European infrastructure 2010 EGU General Assembly Conference Abstracts, pp. 9725  inproceedings
Abstract: RENAG is a collaborative effort from 20 Academic Earth Sciences
Department and Institutes of France. RENAG currently operates
nearly 50 Continuous GPS stations and through agreement with
IGN-France and commercial compagnies, archive and routinely
process about 200 sites covering France with a higher density of
sites in the western Alps. RENAG recently joined RESIF
(http://www.resif.fr), the cpntribution of France to EPOS. RENAG
aims at (1) quantifying the slow tectonic deformation in France
(2) monitoring the deformation induced by the spatial and
temporal variations in continental water loading (3) providing
sea level changes along the French coast with respect to a
global reference frame stable in time through collocated tide-
gauges and CGPS stations (4) monitoring the integrated content
of water vapour in the atmosphere. We detail here the main
results obtained on crustal deformation. France is an area of
moderate seismicity where the associated crustal deformation has
yet to be precisely quantified and understood in the frame of
the regional deformation. We show that the current accuracy of
velocity estimates for the sites operating since 1998 is about
0.3 mm/yr and 0.5 mm/yr on the vertical component (at the 95%
confidence level). Long time-correlated noise in the time series
still prevents to reach the 0.1 mm/yr accuracy. At the level of
0.3 mm/yr, no deformation is detected on the horizontal
components with a WRMS of horizontal velocities with respect to
the Stable Europe Reference Frame of 0.15 mm/yr. However,
vertical velocities in the western Alps reach 1.5 mm/yr, and
show a pattern of increase correlated with the averaged
topography. Because vertical velocities magnitudes are higher
than horizontal ones, the observed vertical deformation is
difficult to be explained by crustal deformation induced either
by current extension associated with gravitationnal spreading or
driven by boundary conditions induced by the counter-clokwise
rotation of the Adriatic, as proposed previously. We therefore
speculate that the current observed vertical deformation
reflects an on-going adjustment having a deeper origin. These
results suggests that monitoring surface deformation in slow
deforming areas and better understand crustal-mantle deformation
within the Mediterranean plate boundary could be added as
objectives of any European plate infrastructure.
BibTeX:
@inproceedings{2010EGUGA..12.9725R,
author = {Renag Group},
title = {RESIF-RENAG : The French GPS component of a European infrastructure},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2010},
pages = {9725}
}

Razak, K.A., Straatsma, M.W., van Westen, C.J., Malet, J.P. and de Jong, S.M. Airborne laser scanning of forested landslides characterization: Terrain model quality and visualization 2011 Geomorphology
Vol. 126(1), pp. 186-200
article DOI
Abstract: Mapping complex landslides under forested terrain requires an
appropriate quality of digital terrain models (DTMs), which
preserve small diagnostic features for landslide classification
such as primary and secondary scarps, cracks, and displacement
structures (flow-type and rigid-type). Optical satellite
imagery, aerial photographs and synthetic aperture radar images
are less effective to create reliable DTMs under tree coverage.
Here, we utilized a very high density airborne laser scanning
(ALS) data, with a point density of 140 points m ^- 2 for
generating a high quality DTM for mapping landslides in forested
terrain in the Barcelonnette region, the Southern French Alps.
We quantitatively evaluated the preservation of morphological
features and qualitatively assessed the visualization of ALS-
derived DTMs. We presented a filter parameterization method
suitable for landslide mapping and compared it with two default
filters from the hierarchical robust interpolation (HRI) and one
default filter from the progressive TIN densification (PTD)
method. The results indicate that the vertical accuracy of the
DTM derived from the landslide filter is about 0.04 m less
accurate than that from the PTD filter. However, the landslide
filter yields a better quality of the image for the recognition
of small diagnostic features as depicted by expert image
interpreters. Several DTM visualization techniques were compared
for visual interpretation. The openness map visualized in a
stereoscopic model reveals more morphologically relevant
features for landslide mapping than the other filter products.
We also analyzed the minimal point density in ALS data for
landslide mapping and found that a point density of more than 6
points m ^- 2 is considered suitable for a detailed
analysis of morphological features. This study illustrates the
suitability of high density ALS data with an appropriate
parameterization for the bare-earth extraction used for
landslide identification and characterization in forested
terrain.
BibTeX:
@article{2011Geomo.126..186R,
author = {Razak, K. A. and Straatsma, M. W. and van Westen, C. J. and Malet, J. -P. and de Jong, S. M.},
title = {Airborne laser scanning of forested landslides characterization: Terrain model quality and visualization},
journal = {Geomorphology},
year = {2011},
volume = {126},
number = {1},
pages = {186-200},
doi = {https://doi.org/10.1016/j.geomorph.2010.11.003}
}

Biessy, G., Moreau, F., Dauteuil, O. and Bour, O. Surface deformation of an intraplate area from GPS time series 2011 Journal of Geodynamics
Vol. 52(1), pp. 24-33
article DOI
Abstract: The aim of this study is to identify the processes that lead to the
ground surface deformation above the fractured crystalline
aquifer of Ploemeur (French Brittany). We conducted a four-year
continuous GPS data survey in order to extract the
hydrogeological contribution due to the variations of the
hydraulic head of the confined aquifer. The GPS configuration
used in this study, with a differential setup, short baselines
and adapted processing parameters, may have removed tide
effects, ocean tide loading and tectonics trends. We checked in
particular the case of ocean tide loading because of its
important contribution in Brittany. Time series calculated with
GAMIT software indicate a seasonal deformation on both vertical
direction (up to 16 mm of displacement) and horizontal plane
(from 3 to 12 mm of displacement) that provide a 3D motion. This
sub-annual deformation is induced by variations of the hydraulic
head of the aquifer and depends on its 3D hydromechanical
properties. However, an offset between ground uplift and
piezometric rise could not be explained by pressure variations
into the deep aquifer and was linked to the variations of the
hydrous state of the ground. This GPS study highlights that the
hydrogeological and hydrological processes act significantly on
ground motion and should be integrated in any Earth deformation
survey.
BibTeX:
@article{2011JGeo...52...24B,
author = {Biessy, G. and Moreau, F. and Dauteuil, O. and Bour, O.},
title = {Surface deformation of an intraplate area from GPS time series},
journal = {Journal of Geodynamics},
year = {2011},
volume = {52},
number = {1},
pages = {24-33},
doi = {https://doi.org/10.1016/j.jog.2010.11.005}
}

Santamar\iA-Gómez, A., Bouin, M.-N., Collilieux, X. and WöPpelmann, G. Correlated errors in GPS position time series: Implications for velocity estimates 2011 Journal of Geophysical Research (Solid Earth)
Vol. 116(B1), pp. B01405
article DOI
Abstract: This study focuses on the effects of time correlation in weekly GPS
position time series on velocity estimates. Time series 2.5 to
13 years long from a homogeneously reprocessed solution of 275
globally distributed stations are analyzed in terms of noise
content and velocity uncertainty assessment. Several noise
models were tested, including power law and Gauss-Markov
processes. The best noise model describing our global data set
was a combination of variable white noise and power law noise
models with mean amplitudes of \sim2 mm and
\sim6 mm, respectively, for the sites considered.
This noise model provided a mean vertical velocity uncertainty
of \sim0.3 mm/yr, 4-5 times larger than the
uncorrelated data assumption. We demonstrated that correlated
noise content with homogeneously reprocessed data is dependent
on time series length and, especially, on data time period. Time
series of 2-3 years of the oldest data contain noise amplitude
similar to that found for time series of 12 years. The data time
period should be taken into account when estimating correlated
noise content, when comparing different noise estimations, or
when applying an external noise estimation to assess velocity
uncertainty. We showed that the data period dependency cannot be
explained by the increasing tracking network or the ambiguity
fixation rate but is probably related to the amount and quality
of recorded data.
BibTeX:
@article{2011JGRB..116.1405S,
author = {Santamar\iA-Gómez, Alvaro and Bouin, Marie-NoëLle and Collilieux, Xavier and WöPpelmann, Guy},
title = {Correlated errors in GPS position time series: Implications for velocity estimates},
journal = {Journal of Geophysical Research (Solid Earth)},
year = {2011},
volume = {116},
number = {B1},
pages = {B01405},
doi = {https://doi.org/10.1029/2010JB007701}
}

Walpersdorf, A., Sue, C., Baize, S., Thirard, L. and Cotte, N. Repeated GPS measurements spanning 15 years to study the extensional deformation regime in the inner southwestern Alps (Briançon region, France) 2012 EGU General Assembly Conference Abstracts, pp. 9508  inproceedings
Abstract: A network of 30 geodetic markers installed in the Briançon region,
southwestern Alps, has been surveyed in 1996, 2006 and 2011 by
GPS. The study zone is characterized by a moderate seismicity
with mainly extensive focal mechanisms and some dextral strike-
slip along N160 oriented faults. The dense temporary GPS network
covering this zone has an extent of 40 x 40 km^2. It is
inserted in the French permanent GPS network for research
purposes (RENAG) starting in 1998, with four permanent stations
located in the study zone, two of them operational since 2005.
Previous analyses combining triangulation data and the 1996 GPS
campaign indicated extensional geodetic deformation rates more
than 10 times higher than seismic deformation. Permanent GPS
analyses of the RENAG network converge since 2000 from
millimetric to sub-millimetric horizontal velocities across the
western Alps, and millimetric vertical velocities indicating
active uplift. While the campaign measurements present an
increased error budget (antenna setup, equipment changes) with
respect to continuous GPS measurements, the observation time
span is longer and the network denser than the permanent GPS
observations, and the two strategies therefore complementary.
Moreover, the combined analysis of up to 13 years of permanent
GPS data and three measurement campaigns over 15 years also
evaluates sub-mm horizontal velocities in the local network. In
this work, we will show if the long observation interval and the
redundancy of the campaign network help constraining a
significant local deformation pattern in the Briançon
region. We will compare the present-day deformation field to the
seismic deformation rate and discuss the implications on seismic
hazard in the Briançon region. We will confront the
instantaneous, geodetic strain pattern with seismotectonic and
morphotectonic observations and examine its impact on the global
geodynamics of the southwestern alpine arc.
BibTeX:
@inproceedings{2012EGUGA..14.9508W,
author = {Walpersdorf, A. and Sue, C. and Baize, S. and Thirard, L. and Cotte, N.},
title = {Repeated GPS measurements spanning 15 years to study the extensional deformation regime in the inner southwestern Alps (Briançon region, France)},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2012},
pages = {9508}
}

Alshawaf, F., Fuhrmann, T., Heck, B., Hinz, S., Knoepfler, A., Luo, X., Mayer, M., Schenk, A., Thiele, A. and Westerhaus, M. Atmospheric Water Vapour Determination By The Integration Of INSAR And GNSS Observations 2012
Vol. 697Fringe 2011, pp. 70
inproceedings
Abstract: High spatial and temporal variations of atmospheric water vapour cause
an unknown delay on microwave signals emitted from space-borne
transmitters. This delay is considered as a major error source
in Interferometric Synthetic Aperture Radar (InSAR) applications
as well as high-precision applications of the Global Navigation
Satellite Systems (GNSS). Temporal variability of water vapour
is estimated directly with a high temporal resolution from GNSS
measurements. On the other hand, InSAR can provide information
about the spatial variations of atmospheric water vapour. The
main goal of this project is to integrate InSAR phase
observations and GNSS measurements collected from sites
distributed within the SAR image to derive high spatially-
resolved maps of atmospheric water vapour. In this contribution
research progress and first results are presented.
BibTeX:
@inproceedings{2012ESASP.697E..70A,
author = {Alshawaf, Fadwa and Fuhrmann, Thomas and Heck, Bernhard and Hinz, Stefan and Knoepfler, Andreas and Luo, Xiaoguang and Mayer, Michael and Schenk, Andreas and Thiele, Antje and Westerhaus, Malte},
title = {Atmospheric Water Vapour Determination By The Integration Of INSAR And GNSS Observations},
booktitle = {Fringe 2011},
year = {2012},
volume = {697},
pages = {70}
}

Santamar\ia-Gómez, A., Gravelle, M., Collilieux, X., Guichard, M., M\iguez, B.M., Tiphaneau, P. and Wöppelmann, G. Mitigating the effects of vertical land motion in tide gauge records using a state-of-the-art GPS velocity field 2012 Global and Planetary Change
Vol. 98-99, pp. 6-17
article DOI
Abstract: This study aims to correct for long-term vertical land motions at tide
gauges (TG) by estimating high-accurate GPS vertical velocities
at co-located stations (GPS@TG), useful for long-term sea-level
change studies and satellite altimeter drift monitoring. Global
Positioning System (GPS) data reanalyses are mandatory when
aiming at the highest consistency of the estimated products for
the whole data period. The University of La Rochelle Consortium
(ULR) has carried out several GPS data reanalysis campaigns with
an increasing tracking network, an improving processing strategy
and the best methodology. The geodetic results from the latest
GPS velocity field estimated at ULR (named ULR5) are presented
here. The velocity field includes 326 globally distributed GPS
stations, from which 200 are GPS@TG (30% more than previous
studies). The new GPS data processing strategy, the terrestrial
frame definition and the velocity estimation procedures are
described. The quality of the estimated vertical velocities is
empirically assessed through internal and external velocity
comparisons, including the analysis of the time-correlated noise
content of the position time series, to be better than 0.6 mm/yr
(2 sigma). The application of this velocity field is illustrated
to appraise to what extent vertical land motions contaminate the
estimates of satellite altimetry drifts. The impact on the
altimeter-derived sea level trends was evaluated to be up to 0.6
mm/yr. Worldwide TGs were grouped into regions in order to
explore long-term spatial sea level variability in the rates of
sea level change. By taking into account the vertical land
motion of the tide gauges, the dispersion of the observed sea
level rates within each region was reduced by 60%. Long-term
regional mean sea level variations up to 70% from the global
mean were found.
BibTeX:
@article{2012GPC....98....6S,
author = {Santamar\ia-Gómez, A. and Gravelle, M. and Collilieux, X. and Guichard, M. and M\iguez, B. Mart\in and Tiphaneau, P. and Wöppelmann, G.},
title = {Mitigating the effects of vertical land motion in tide gauge records using a state-of-the-art GPS velocity field},
journal = {Global and Planetary Change},
year = {2012},
volume = {98-99},
pages = {6-17},
doi = {https://doi.org/10.1016/j.gloplacha.2012.07.007}
}

Nocquet, J.-M. Present-day kinematics of the Mediterranean: A comprehensive overview of GPS results 2012 Tectonophysics
Vol. 579, pp. 220-242
article DOI
Abstract: I combine recently published GPS results to derive a geodetic horizontal
velocity field consistent at the scale of the Mediterranean and
the surrounding Alpine belts. The velocity field is then used to
discuss the boundary conditions around each major deforming area
in the Mediterranean, to describe the main patterns of motion
and deformation, to critically review the existing kinematics
models and to finally point out the main unresolved kinematics
questions. Strain rate in Europe north of the Alpines belt is
dominated by the signature of the Glacial Isostatic Adjustment
and tectonic strain remains below the current accuracy of GPS
results. In the western Mediterranean, deformation is restricted
to the Betics, the Alboran and the Morrocan Rif, with west-to-
southwestward motion with respect to Iberia, which is part of
stable Europe. Shortening, consistent with the relative
Nubia/Eurasia plate motion, is found throughout the Maghrebides,
but the distribution of deformation in northern Africa remains
largely unknown. The central Mediterranean is dominated by the
counter-clockwise rotation of the Adriatic. The junction between
the southern Adriatic domain and Nubia has yet to be firmly
established. The deformation over a wide area, east of the
Maghrebides, in Tunisia and the gulf of Sirte in Libya still
remains to be quantified. In the eastern Mediterranean, the
velocity field is dominated by a general anti-clockwise rotation
and a general trend towards the Hellenic trench, with velocity
magnitude increasing with decreasing distances from the trench.
This trend is observed not only in the Aegean and Anatolia, but
also in the southern Balkans. Geodetic results emphasize that
the convergence of the Nubia and Arabia plates towards Eurasia
directly controls the deformation across only very few segments
along the plate boundary zone. Additional processes are
therefore required to explain the observed velocity field and
deformation pattern.
BibTeX:
@article{2012Tectp.579..220N,
author = {Nocquet, Jean-Mathieu},
title = {Present-day kinematics of the Mediterranean: A comprehensive overview of GPS results},
journal = {Tectonophysics},
year = {2012},
volume = {579},
pages = {220-242},
doi = {https://doi.org/10.1016/j.tecto.2012.03.037}
}

Langlais, M., Vial, B. and Coutant, O. Improvement of broadband seismic station installations at the Observatoire de Grenoble (OSUG) seismic network 2013 Advances in Geosciences
Vol. 34, pp. 9-14
article DOI
Abstract: We describe in this paper different improvements that were brought to
the installation of seismic broadband stations deployed by the
Observatoire de Grenoble (OSUG) in the northern French Alps.
This work was realized in the frame of a French-Italian ALCOTRA
project (RISE), aimed at modernizing the broadband seismic
networks across our common border. We had the opportunity with
this project to improve some of our seismic recording sites,
both in term of sensor installation quality, and in term of
reliability. We detail in particular the thermal and barometric
protection system that we designed and show its effect on the
reduction of long period noise above 20 s.
BibTeX:
@article{2013AdG....34....9L,
author = {Langlais, M. and Vial, B. and Coutant, O.},
title = {Improvement of broadband seismic station installations at the Observatoire de Grenoble (OSUG) seismic network},
journal = {Advances in Geosciences},
year = {2013},
volume = {34},
pages = {9-14},
}

Fuhrmann, T., Knopfler, A., Mayer, M., Schenk, A., Westerhaus, M., Zippelt, K. and Heck, B. Towards A Fusion Of SAR-Interferometry, GNSS And Precise Levelling In The Upper Rhine Graben Area, Southwest Germany 2013
Vol. 722ESA Living Planet Symposium, pp. 57
inproceedings
Abstract: InSAR, GNSS and precise levelling provide a unique database to detect
recent displacements of the Earth's surface. Data of all three
measurement techniques have been collected in order to gain
detailed insight into the horizontal and vertical velocity field
of the Upper Rhine Graben (URG) area. This paper presents the
database and the processing strategies for the calculation of
displacements from InSAR, GNSS and levelling measurements in the
URG area. Man-induced surface deformations caused by oil
extraction in the Northern URG are investigated serving as a
study area for the comparison of techniques. In order to benefit
from the advantages of each technique we present a strategy to
consistently link the different observation methods in a multi-
technique approach.
BibTeX:
@inproceedings{2013ESASP.722E..57F,
author = {Fuhrmann, T. and Knopfler, A. and Mayer, M. and Schenk, A. and Westerhaus, M. and Zippelt, K. and Heck, B.},
title = {Towards A Fusion Of SAR-Interferometry, GNSS And Precise Levelling In The Upper Rhine Graben Area, Southwest Germany},
booktitle = {ESA Living Planet Symposium},
year = {2013},
volume = {722},
pages = {57}
}

Fuhrmann, T., Heck, B., Knöpfler, A., Masson, F., Mayer, M., Ulrich, P., Westerhaus, M. and Zippelt, K. Recent surface displacements in the Upper Rhine Graben — Preliminary results from geodetic networks 2013 Tectonophysics
Vol. 602, pp. 300-315
article DOI
Abstract: Datasets of the GNSS Upper Rhine Graben Network (GURN) and the national
levelling networks in Germany, France and Switzerland are
investigated with respect to current surface displacements in
the Upper Rhine Graben (URG) area. GURN consists of about 80
permanent GNSS (Global Navigation Satellite Systems) stations.
The terrestrial levelling network comprises 1st and 2nd order
levelling lines that have been remeasured at intervals of
roughly 25 years, starting in 1922. Compared to earlier studies
national institutions and private companies made available raw
data, allowing for consistent solutions for the URG region. We
focussed on the southern and eastern parts of the investigation
area. Our preliminary results show that the levelling and GNSS
datasets are sensitive to resolve small surface displacement
rates down to an order of magnitude of 0.2 mm/a and 0.4 mm/a,
respectively. The observed horizontal velocity components for a
test region south of Strasbourg, obtained from GNSS coordinate
time series, vary around 0.5 mm/a. The results are in general
agreement with interseismic strain built-up in a sinistral
strike-slip regime. Since the accuracy of the GNSS derived
vertical component is insufficient, data of precise levelling
networks is used to determine vertical displacement rates. More
than 75% of the vertical rates obtained from a kinematic
adjustment of 1st order levelling lines in the eastern part of
URG vary between - 0.2 mm/a and + 0.2 mm/a, indicating that this
region behaves stable. Higher rates up to 0.5 mm/a in a limited
region south of Freiburg are in general agreement with active
faulting. We conclude that both networks deliver stable results
that reflect real surface movements in the URG area. We note,
however, that geodetically observed surface displacements
generally result from a superposition of different effects, and
that a separation in tectonic and non-tectonic processes needs
additional information and expertise.
BibTeX:
@article{2013Tectp.602..300F,
author = {Fuhrmann, Thomas and Heck, Bernhard and Knöpfler, Andreas and Masson, Frédéric and Mayer, Michael and Ulrich, Patrice and Westerhaus, Malte and Zippelt, Karl},
title = {Recent surface displacements in the Upper Rhine Graben — Preliminary results from geodetic networks},
journal = {Tectonophysics},
year = {2013},
volume = {602},
pages = {300-315},
doi = {https://doi.org/10.1016/j.tecto.2012.10.012}
}

Brenot, H., Walpersdorf, A., Reverdy, M., van Baelen, J., Ducrocq, V., Champollion, C., Masson, F., Doerflinger, E., Collard, P. and Giroux, P. A GPS network for tropospheric tomography in the framework of the Mediterranean hydrometeorological observatory Cévennes-Vivarais (southeastern France) 2014 Atmospheric Measurement Techniques
Vol. 7(2), pp. 553-578
article DOI
Abstract: The Mediterranean hydrometeorological observatory Cévennes-Vivarais
(OHM-CV) coordinates hydrometeorological observations (radars,
rain gauges, water level stations) on a regional scale in
southeastern France. In the framework of OHM-CV, temporary GPS
measurements have been carried out for 2 months in autumn 2002,
when the heaviest rainfall are expected. These measurements
increase the spatial density of the existing permanent GPS
network, by adding three more receivers between the
Mediterranean coast and the Cévennes-Vivarais range to
monitor maritime source of water vapour flow feeding the
precipitating systems over the Cévennes-Vivarais region. In
addition, a local network of 18 receivers covered an area of 30
by 30 km within the field of view of the meteorological radar.
These regional and local networks of permanent and temporary
stations are used to monitor the precipitable water vapour (PWV)
with high temporal resolution (15 min). Also, the dense local
network provided data which have been inverted using tomographic
techniques to obtain the 3-D field of tropospheric water vapour
content. This study presents methodological tests for retrieving
GPS tropospheric observations from dense networks, with the aim
of assessing the uncertainties of GPS retrievals. Using optimal
tropospheric GPS retrieval methods, high resolution measurements
of PWV on a local scale (a few kilometres) are discussed for
rain events. Finally, the results of 3-D fields of water vapour
densities from GPS tomography are analysed with respect to
precipitation fields derived from a meteorological radar,
showing a good correlation between precipitation and water
vapour depletion areas.
BibTeX:
@article{2014AMT.....7..553B,
author = {Brenot, H. and Walpersdorf, A. and Reverdy, M. and van Baelen, J. and Ducrocq, V. and Champollion, C. and Masson, F. and Doerflinger, E. and Collard, P. and Giroux, P.},
title = {A GPS network for tropospheric tomography in the framework of the Mediterranean hydrometeorological observatory Cévennes-Vivarais (southeastern France)},
journal = {Atmospheric Measurement Techniques},
year = {2014},
volume = {7},
number = {2},
pages = {553-578},
doi = {https://doi.org/10.5194/amt-7-553-2014}
}

Sue, C., Walpersdorf, A., Sakic, P., Rabin, M. and Champagnac, J.d. Permanent GPS network around the bend of the Jura Arc: preliminary results 2014 EGU General Assembly Conference Abstracts, pp. 11026  inproceedings
Abstract: The Jura Mountain, the westernmost belt of the alpine orogeny, is one of
the best-studied orogenic arcs in the world. The Jura arc is a
typical fold-and-thrust belt, with a main décollement thrust
localized in the Triasic evaporites under the Jurassic-
Cretaceous series. It is directly linked to the alpine orogenic
wedge, especially in term of critical taper. It is supposed to
be still active in collision mode, which would rise up the issue
of its relation with the Alps to the East, currently undergoing
post-orogenic gravitational potential adjustment. Nevertheless,
its current activity and recent deformation remain a matter of
debate, few neotectonic-related data being available in this
area. The Jura is crosscut by left-lateral strike-slip faults in
a radial scheme with respect to the arc, and recent seismicity
along one of them, the Vuache fault (Annecy earthquake Ml 5.3
1996), and at the northern front of the belt (Beaume-les-Dames
earthquake, Ml 5.1, 2004), argues for ongoing active deformation
across the Jura Mountain. Here we present preliminary results of
permanent GPS network surrounding the Jura belt (RENAG and RPG
data), which tend to show very slow, yet self-consistent strain
pattern of the order of some tenth of mm/yr over 100 km-long
typical baselines, with shortening perpendicular to the arc, and
extension parallel to its axial trend. We also characterize a
slow uplift in the same order of magnitude, which appears to be
correlated to the current uplift observed in the Alps. Indeed,
the uplift velocities are continuously decreasing from the core
of the Alps (+2 mm/yr) to the westernmost part of the Jura (+0,4
mm/yr) and to the stable foreland (-0.1 mm/yr). Actually, from
the Po plain to the Jura foreland, the GPS-related uplift
velocities are well correlated to the topography, and the Jura
arc appears connected to the Alps from this point of view. In
order to better determine the deformation pattern in the Jura
arc, we present a new regional GNSS permanent network (GPS-JURA,
Besançon observatory) developed at the end of 2013, which
will allow in a near future to accurately characterize and
quantify the current strain pattern of this emblematic arc.
BibTeX:
@inproceedings{2014EGUGA..1611026S,
author = {Sue, Christian and Walpersdorf, Andrea and Sakic, Pierre and Rabin, Mickael and Champagnac, Jean daniel},
title = {Permanent GPS network around the bend of the Jura Arc: preliminary results},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2014},
pages = {11026}
}

Boler, F., Wier, S., D'Agostino, N., Fernandes, R.R.M., Ganas, A., Bruyninx, C. and Ofeigsson, B. New Collaboration Among Geodesy Data Centers in Europe and the US Facilitates Data Discovery and Access 2014 EGU General Assembly Conference Abstracts, pp. 12385  inproceedings
Abstract: COOPEUS, the European Union project to strengthen the cooperation
between the US and the EU in the field of environmental research
infrastructures, is linking the US NSF-supported geodesy
Facility at UNAVCO with the European Plate Observing System
(EPOS) in joint research infrastructure enhancement activities
that will ultimately advance international geodesy data
discovery and access. (COOPEUS also links a broad set of
additional EU and US based Earth, oceans, and environmental
science research entities in joint research infrastructure
enhancement activities.) The UNAVCO Data Center in Boulder,
Colorado, archives for preservation and distributes geodesy data
and products, including hosting GNSS data from 2,500
continuously operating stations around the globe. UNAVCO is only
one of several hundred data centers worldwide hosting GNSS data,
which are valuable for scientific research, education, hazards
assessment and monitoring, and emergency management. However,
the disparate data holdings structures, metadata encodings, and
infrastructures at these data centers represent a significant
obstacle to use by scientists, government entities, educators
and the public. Recently a NASA-funded project at UNAVCO and two
partner geodesy data centers in the US (CDDIS and SOPAC) has
successfully designed and implemented software for simplified
data search and access called the Geodesy Seamless Archive
Centers (GSAC). GSAC is a web services based technology that is
intended to be simple to install and run for most geodesy data
centers. The GSAC services utilize a repository layer and a
service layer to identify and present both the required metadata
elements along with any data center-specific services and
capabilities. In addition to enabling web services and related
capabilities at the data center level, GSAC repository code can
be implemented to federate two or more GSAC-enabled data centers
wishing to present a unified search and access capability to
their user community. In Europe, several institutions that are
part of EPOS including University of Beira Interior (Portugal);
Istituto Nazionale di Geofisica e Vulcanologia (Italy); National
Observatory of Athens (Greece); RENAG, GeoAzur (France);
Vedurstofa Islands (Iceland Meteorological Office), and EUREF
Permanent Network Central Bureau (Belgium), each host data from
GNSS station networks. These EPOS members have all implemented
GSAC at their respective data centers for internal testing
and/or public utilization. In the US, GSAC has been successfully
used in both repository and federated implementations at three
data centers, each maintaining their own local information
architecture to manage their respective data and metadata
holdings. These capacities of GSAC will also be utilized in the
EPOS context. Lessons have been learned through the GSAC
installations so far that show the way for augmenting data
center information architecture to both maximize the
capabilities of GSAC to allow unified data and metadata
presentation for search and access.
BibTeX:
@inproceedings{2014EGUGA..1612385B,
author = {Boler, Fran and Wier, Stuart and D'Agostino, Nicola and Fernandes, Rui R. M. and Ganas, Athanassios and Bruyninx, Carine and Ofeigsson, Benedikt},
title = {New Collaboration Among Geodesy Data Centers in Europe and the US Facilitates Data Discovery and Access},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2014},
pages = {12385}
}

Kreemer, C., Blewitt, G. and Klein, E.C. A geodetic plate motion and Global Strain Rate Model 2014 Geochemistry, Geophysics, Geosystems
Vol. 15(10), pp. 3849-3889
article DOI
Abstract: We present a new global model of plate motions and strain rates in plate
boundary zones constrained by horizontal geodetic velocities.
This Global Strain Rate Model (GSRM v.2.1) is a vast improvement
over its predecessor both in terms of amount of data input as in
an increase in spatial model resolution by factor of
\sim2.5 in areas with dense data coverage. We
determined 6739 velocities from time series of (mostly)
continuous GPS measurements; i.e., by far the largest global
velocity solution to date. We transformed 15,772 velocities from
233 (mostly) published studies onto our core solution to obtain
22,511 velocities in the same reference frame. Care is taken to
not use velocities from stations (or time periods) that are
affected by transient phenomena; i.e., this data set consists of
velocities best representing the interseismic plate velocity.
About 14% of the Earth is allowed to deform in 145,086
deforming grid cells (0.25textdegree longitude by
0.2textdegree latitude in dimension). The remainder of the
Earth's surface is modeled as rigid spherical caps representing
50 tectonic plates. For 36 plates we present new GPS-derived
angular velocities. For all the plates that can be compared with
the most recent geologic plate motion model, we find that the
difference in angular velocity is significant. The rigid-body
rotations are used as boundary conditions in the strain rate
calculations. The strain rate field is modeled using the Haines
and Holt method, which uses splines to obtain an self-consistent
interpolated velocity gradient tensor field, from which strain
rates, vorticity rates, and expected velocities are derived. We
also present expected faulting orientations in areas with
significant vorticity, and update the no-net rotation reference
frame associated with our global velocity gradient field.
Finally, we present a global map of recurrence times for
M_w=7.5 characteristic earthquakes.
BibTeX:
@article{2014GGG....15.3849K,
author = {Kreemer, Corné and Blewitt, Geoffrey and Klein, Elliot C.},
title = {A geodetic plate motion and Global Strain Rate Model},
journal = {Geochemistry, Geophysics, Geosystems},
year = {2014},
volume = {15},
number = {10},
pages = {3849-3889},
doi = {https://doi.org/10.1002/2014GC005407}
}

Fuhrmann, T., Caro Cuenca, M., Knopfler, A., van Leijen, F.J., Mayer, M., Westerhaus, M., Hanssen, R.F. and Heck, B. Combining InSAR Leveling and GNSS for the Estimation of 3D Surface Displacements 2015
Vol. 731FRINGE 2015, pp. 8
inproceedings
Abstract: The three geodetic techniques InSAR, levelling and GNSS are
complementary w.r.t. (i) the sensitivity to horizontal and
vertical displacement components, (ii) the spatial and temporal
resolution of the measurements and (iii) the accuracy of the
resulting displacements. We present a strategy to robustly
combine the displacement estimates of the three techniques with
a focus on long-term, linear movements. The linear displacement
rates from InSAR in ascending and descending image geometry are
combined with vertical and horizontal rates from levelling and
GNSS, respectively, resulting in 3D velocity vectors at a dense
surface grid. The results of our combination approach indicate
that it is possible to derive realistic surface movements on the
sub-mm/a scale with significance.
BibTeX:
@inproceedings{2015ESASP.731E...8F,
author = {Fuhrmann, T. and Caro Cuenca, M. and Knopfler, A. and van Leijen, F. J. and Mayer, M. and Westerhaus, M. and Hanssen, R. F. and Heck, B.},
title = {Combining InSAR Leveling and GNSS for the Estimation of 3D Surface Displacements},
booktitle = {FRINGE 2015},
year = {2015},
volume = {731},
pages = {8}
}

Fuhrmann, T., Caro Cuenca, M., Knöpfler, A., van Leijen, F.J., Mayer, M., Westerhaus, M., Hanssen, R.F. and Heck, B. Estimation of small surface displacements in the Upper Rhine Graben area from a combined analysis of PS-InSAR, levelling and GNSS data 2015 Geophysical Journal International
Vol. 203(1), pp. 614-631
article DOI
Abstract: The intra-plate deformation of the Upper Rhine Graben (URG) located in
Central Europe is investigated using geodetic measurement
techniques. We present a new approach to calculate a combined
velocity field from InSAR, levelling and GNSS measurements. As
the expected tectonic movements in the URG area are small (less
than 1 mm a^-1), the best possible solutions for linear
velocity rates from single-technique analyses are estimated in a
first step. Second, we combine the velocity rates obtained from
InSAR (line of sight velocity rates in ascending and descending
image geometries), levelling (vertical velocity rates) and GNSS
(horizontal velocity rates) using least-squares adjustment
(LSA). Focusing on the Northern URG area, we analyse SAR data on
four different image stacks (ERS ascending, ERS descending,
Envisat ascending, Envisat descending) using the Persistent
Scatterer (PS) approach. The linear velocity rates in ascending
and descending image geometries, respectively, are estimated in
an LSA from joint time-series analysis of ERS and Envisat data.
Vertical velocity rates from levelling are obtained from a
consistent adjustment of more than 40 000 measured height
differences using a kinematic displacement model. Horizontal
velocity rates in east and north direction are calculated from a
time-series analysis of daily coordinate estimates at 76
permanently operating GNSS sites in the URG region. As the
locations, at which the measurement data of PS-InSAR, levelling
and GNSS reside, do not coincide, spatial interpolation is
needed during several steps of the rigorous processing. We use
Ordinary Kriging to interpolate from a given set of data points
to the locations of interest with a special focus on the
modeling and propagation of errors. The final 3-D velocity field
is calculated at a 200 m grid, which carries values only close
to the location of PS points, resulting in a mean horizontal and
vertical precision of 0.30 and 0.13 mm a^-1, respectively.
The vertical component of the combined velocity field shows a
significant subsidence of about 0.5 mm a^-1 in the northern
part of the graben coinciding with a well-known quaternary basin
structure. Horizontal displacement rates of up to 0.8 mm
a^-1 in southeast direction are observed outside the graben,
in reasonable alignment with the average direction of maximum
horizontal stress. Within the graben, the velocity directions
rotate toward east in the non-subsiding part, while an opposite
trend is observed in the subsiding part of the graben. The
complexities of the observed velocity field are compatible to
the geomechanical situation in our investigation area which is
characterized by a transition from a restraining to a releasing
bend setting. Glacial isostatic adjustment is another potential
source influencing the observed velocity field, as well as
anthropogenic signals due to mining, oil exploration and
groundwater usage that have been identified in some places.
BibTeX:
@article{2015GeoJI.203..614F,
author = {Fuhrmann, T. and Caro Cuenca, M. and Knöpfler, A. and van Leijen, F. J. and Mayer, M. and Westerhaus, M. and Hanssen, R. F. and Heck, B.},
title = {Estimation of small surface displacements in the Upper Rhine Graben area from a combined analysis of PS-InSAR, levelling and GNSS data},
journal = {Geophysical Journal International},
year = {2015},
volume = {203},
number = {1},
pages = {614-631},
doi = {https://doi.org/10.1093/gji/ggv328}
}

Zhang, S.-R., Erickson, P.J., Foster, J.C., Holt, J.M., Coster, A.J., Makela, J.J., Noto, J., Meriwether, J.W., Harding, B.J., Riccobono, J. and Kerr, R.B. Thermospheric poleward wind surge at midlatitudes during great storm intervals 2015 Geophysical Research Letter
Vol. 42(13), pp. 5132-5140
article DOI
Abstract: We report a significant poleward surge in thermospheric winds at
subauroral and midlatitudes following the 17-18 March 2015 great
geomagnetic storm. This premidnight surge is preceded by strong
westward winds. These disturbances were observed over three
sites with geodetic latitudes 35-42textdegreeN in the
American sector by Fabry-Perot interferometers at 630 nm
wavelength. Prior to the wind disturbances, subauroral
polarization streams (SAPS) were measured by the Millstone Hill
incoherent scatter radar between 20 and 02 UT. We identify the
observed neutral wind variations as driven by SAPS, through a
scenario where strong ion flows cause a westward neutral wind,
subsequently establishing a poleward wind surge due to the
poleward Coriolis force on that westward wind. These regional
disturbances appear to have prevented the well-known storm time
equatorward wind surge from propagating into low latitudes, with
the consequence that the classic disturbance dynamo mechanism
failed to occur.
BibTeX:
@article{2015GeoRL..42.5132Z,
author = {Zhang, Shun-Rong and Erickson, Philip J. and Foster, John C. and Holt, John M. and Coster, Anthea J. and Makela, Jonathan J. and Noto, John and Meriwether, John W. and Harding, Brian J. and Riccobono, Juanita and Kerr, Robert B.},
title = {Thermospheric poleward wind surge at midlatitudes during great storm intervals},
journal = {Geophysical Research Letter},
year = {2015},
volume = {42},
number = {13},
pages = {5132-5140},
doi = {https://doi.org/10.1002/2015GL064836}
}

Labbouz, L., Van Baelen, J. and Duroure, C. Investigation of the links between water vapor field evolution and rain rate based on 5 years of measurements at a midlatitude site 2015 Geophysical Research Letter
Vol. 42(21), pp. 9538-9545
article DOI
Abstract: Based on 5 years of measurements of integrated water vapor (IWV),
surface mixing ratio (MR), and rain rate, we investigate the
relationship between the water vapor field evolution and the
precipitation lifecycle. We show that in 76% of the cases the
IWV reaches a maximum before the peak of precipitation, with the
precipitation peak occurring on average 20 min after the IWV
maximum. This delay can be related to the fall time of the
precipitation. We also show that the moister the atmosphere, the
greater the precipitation rates and the longer the delay. Unlike
the IWV, the MR reaches a maximum after the precipitation peak
in 60% of the cases, highlighting the interest of IWV compared
to surface MR only. This paper and the discussions within it
open a pathway to complementary studies and applications for
heavy precipitation prediction.
BibTeX:
@article{2015GeoRL..42.9538L,
author = {Labbouz, Laurent and Van Baelen, Joël. and Duroure, Christophe},
title = {Investigation of the links between water vapor field evolution and rain rate based on 5 years of measurements at a midlatitude site},
journal = {Geophysical Research Letter},
year = {2015},
volume = {42},
number = {21},
pages = {9538-9545},
doi = {https://doi.org/10.1002/2015GL066048}
}

Walpersdorf, A., Sue, C., Baize, S., Cotte, N., Bascou, P., Beauval, C., Collard, P., Daniel, G., Dyer, H., Grasso, J.R., Hautecoeur, O., Helmstetter, A., Hok, S., Langlais, M., Menard, G., Mousavi, Z., Ponton, F., Rizza, M., Rolland, L., Souami, D., Thirard, L., Vaudey, P., Voisin, C. and Martinod, J. Coherence between geodetic and seismic deformation in a context of slow tectonic activity (SW Alps, France) 2015 Journal of Geodynamics
Vol. 85, pp. 58-65
article DOI
Abstract: A dense, local network of 30 geodetic markers covering a 50 texttimes
60 km^2 area in the southwestern European Alps
(Briançon region) has been temporarily surveyed in 1996,
2006 and 2011 by GPS. The aim is to measure the current
deformation in this seismically active area. The study zone is
characterized by a majority of extensional and dextral focal
mechanisms, along north-south to N160 oriented faults. The
combined analysis of the three measurement campaigns over 15
years and up to 16 years of permanent GPS data from the French
RENAG network now enables to assess horizontal velocities below
1 mm/year within the local network. The long observation
interval and the redundancy of the dense campaign network
measurement help to constrain a significant local deformation
pattern in the Briançon region, yielding an average E-W
extension of 16 \pm 11 nanostrain/year. We
compare the geodetic deformation field to the seismic
deformation rate cumulated over 37 years, and obtain good
coherencies both in amplitude and direction. Moreover, the
horizontal deformation localized in the Briançon region
represents a major part of the Adriatic-European relative plate
motion. However, the average uplift of the network in an
extensional setting needs the presence of buoyancy forces in
addition to plate tectonics.
BibTeX:
@article{2015JGeo...85...58W,
author = {Walpersdorf, A. and Sue, C. and Baize, S. and Cotte, N. and Bascou, P. and Beauval, C. and Collard, P. and Daniel, G. and Dyer, H. and Grasso, J. -R. and Hautecoeur, O. and Helmstetter, A. and Hok, S. and Langlais, M. and Menard, G. and Mousavi, Z. and Ponton, F. and Rizza, M. and Rolland, L. and Souami, D. and Thirard, L. and Vaudey, P. and Voisin, C. and Martinod, J.},
title = {Coherence between geodetic and seismic deformation in a context of slow tectonic activity (SW Alps, France)},
journal = {Journal of Geodynamics},
year = {2015},
volume = {85},
pages = {58-65},
doi = {https://doi.org/10.1016/j.jog.2015.02.001}
}

Alshawaf, F., Hinz, S., Mayer, M. and Meyer, F.J. Constructing accurate maps of atmospheric water vapor by combining interferometric synthetic aperture radar and GNSS observations 2015 Journal of Geophysical Research (Atmospheres)
Vol. 120(4), pp. 1391-1403
article DOI
Abstract: Over the past 20years, repeat-pass spaceborne interferometric synthetic
aperture radar (InSAR) has been widely used as a geodetic
technique to generate maps of the Earth's topography and to
measure the Earth's surface deformation. In this paper, we
present a new approach to exploit microwave data from InSAR,
particularly Persistent Scatterer InSAR (PSI), and Global
Navigation Satellite Systems (GNSS) to derive maps of the
absolute water vapor content in the Earth's atmosphere.
Atmospheric water vapor results in a phase shift in the InSAR
interferogram, which if successfully separated from other phase
components provides valuable information about its distribution.
PSI produces precipitable water vapor (PWV) difference maps of a
high spatial density, which can be inverted using the least
squares method to retrieve PWV maps at each SAR acquisition
time. These maps do not contain the absolute (total) PWV along
the signal path but only a part of it. The components eliminated
by forming interferograms or phase filtering during PSI data
processing are reconstructed using GNSS phase observations. The
approach is applied to build maps of absolute PWV by combining
data from InSAR and GNSS over the region of Upper Rhine Graben
in Germany and France. For validation, we compared the derived
PWV maps with PWV maps measured by the optical sensor MEdium-
Resolution Imaging Spectrometer. The results show strong spatial
correlation with values of uncertainty of less than 1.5mm.
Continuous grids of PWV are then produced by applying the
kriging geostatistical interpolation technique that exploits the
spatial correlations between the PWV observations.
BibTeX:
@article{2015JGRD..120.1391A,
author = {Alshawaf, Fadwa and Hinz, Stefan and Mayer, Michael and Meyer, Franz J.},
title = {Constructing accurate maps of atmospheric water vapor by combining interferometric synthetic aperture radar and GNSS observations},
journal = {Journal of Geophysical Research (Atmospheres)},
year = {2015},
volume = {120},
number = {4},
pages = {1391-1403},
doi = {https://doi.org/10.1002/2014JD022419}
}

Park, J., Kil, H., Stolle, C., Lühr, H., Coley, W.R., Coster, A. and Kwak, Y.-S. Daytime midlatitude plasma depletions observed by Swarm: Topside signatures of the rocket exhaust 2016 Geophysical Research Letter
Vol. 43(5), pp. 1802-1809
article DOI
Abstract: The daytime midlatitude plasma depletions (DMLPDs) observed on 22 May
2014 and 20 May 2015 by the Swarm constellation are not
explained by any known natural phenomena. The DMLPDs were
detected after rocket launches, and the DMLPD traces converged
to the launch station. The event in 2015, for which sufficient
total electron content (TEC) data are available, is accompanied
with TEC depletion lasting for about 6 h. The persistence
generally agrees with the lifetime expected for rocket exhaust
depletions (REDs) which is determined by the recombination of
the ionospheric oxygen ion with water molecules in the rocket
exhaust. These results lead to the conclusion that DMLPDs are
REDs in the topside. The RED characteristics identified from the
observations on both days are (1) enhancement in electron
temperature, (2) reduction in electron pressure, and (3) absence
of substructures down to scale sizes of about 8 km (Nyquist's
scale size).
BibTeX:
@article{2016GeoRL..43.1802P,
author = {Park, Jaeheung and Kil, Hyosub and Stolle, Claudia and Lühr, Hermann and Coley, William R. and Coster, Anthea and Kwak, Young-Sil},
title = {Daytime midlatitude plasma depletions observed by Swarm: Topside signatures of the rocket exhaust},
journal = {Geophysical Research Letter},
year = {2016},
volume = {43},
number = {5},
pages = {1802-1809},
doi = {https://doi.org/10.1002/2016GL067810}
}

David, M., Sojka, J.J., Schunk, R.W. and Coster, A.J. Polar cap patches and the tongue of ionization: A survey of GPS TEC maps from 2009 to 2015 2016 Geophysical Research Letter
Vol. 43(6), pp. 2422-2428
article DOI
Abstract: The source and structuring mechanisms for F region density patches have
been subjects of speculation and debate for many years. We have
made a survey of mappings of total electron content (TEC)
between the years 2009 and 2015 from the web-based Madrigal data
server in order to determine when patches and/or a tongue of
ionization (TOI) have been present in the Northern Hemisphere
polar cap; we find that there is a UT and seasonal dependence
that follows a specific pattern. This finding sheds considerable
light upon the old question of the source of polar cap patches,
since it virtually eliminates potential patch plasma sources
that do not have a UT/seasonal dependence, for example, particle
precipitation or flux transfer events. We also find that the
frequency of occurrence of patches or TOIs has little to do with
the level of geomagnetic activity.
BibTeX:
@article{2016GeoRL..43.2422D,
author = {David, Michael and Sojka, J. J. and Schunk, R. W. and Coster, A. J.},
title = {Polar cap patches and the tongue of ionization: A survey of GPS TEC maps from 2009 to 2015},
journal = {Geophysical Research Letter},
year = {2016},
volume = {43},
number = {6},
pages = {2422-2428},
doi = {https://doi.org/10.1002/2016GL068136}
}

Thomas, E.G., Baker, J.B.H., Ruohoniemi, J.M., Coster, A.J. and Zhang, S.R. The geomagnetic storm time response of GPS total electron content in the North American sector 2016 Journal of Geophysical Research (Space Physics)
Vol. 121(2), pp. 1744-1759
article DOI
Abstract: Over the last two decades, maps of GPS total electron content (TEC) have
improved our understanding of the large perturbations in
ionospheric electron density which occur during geomagnetic
storms. However, previous regional and global studies of
ionospheric storms have performed only a limited separation of
storm time, local time, longitudinal, and seasonal effects.
Using 13 years of GPS TEC data, we present a complete
statistical characterization of the ionospheric response to
geomagnetic storms for midlatitudes in the North American sector
where dense ground receiver coverage is available. The rapid
onset of a positive phase is observed across much of the dayside
and evening ionosphere followed by a longer-lasting negative
phase across all latitudes and local times. Our results show
clear seasonal variations in the storm time TEC, such that
summer events tend to be dominated by the negative storm
response while winter events exhibit a stronger initial positive
phase with minimal negative storm effects. We find no
discernable difference between spring and fall equinox events
with both being equivalent to the average storm time response
across all seasons. We also identify a prominent magnetic
declination effect such that stronger dayside positive storm
effects are observed in regions of negative declination (i.e.,
eastern North America). On the nightside, asymmetries in the TEC
response are observed near the auroral oval and midlatitude
trough which may be attributed to thermospheric zonal winds
pushing plasma upward/downward along field lines of opposite
declination.
BibTeX:
@article{2016JGRA..121.1744T,
author = {Thomas, E. G. and Baker, J. B. H. and Ruohoniemi, J. M. and Coster, A. J. and Zhang, S. -R.},
title = {The geomagnetic storm time response of GPS total electron content in the North American sector},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2016},
volume = {121},
number = {2},
pages = {1744-1759},
doi = {https://doi.org/10.1002/2015JA022182}
}

Yang, S.-G., Zhang, B.-C., Fang, H.-X., Kamide, Y., Li, C.-Y., Liu, J.-M., Zhang, S.-R., Liu, R.-Y., Zhang, Q.-H. and Hu, H.-Q. New evidence of dayside plasma transportation over the polar cap to the prevailing dawn sector in the polar upper atmosphere for solar-maximum winter 2016 Journal of Geophysical Research (Space Physics)
Vol. 121(6), pp. 5626-5638
article DOI
Abstract: It is well known that owing to the transport of high-density sunlit
plasma from dayside to nightside primarily by convection, polar
cap tongue of ionization (TOI), polar cap patches, and blobs are
common features in the polar ionosphere. The steep density
gradients at the edges of these structures lead to severe
problems in applications involving radio waves traversing the
ionosphere. To better understand the evolution of
TOI/patches/blobs, it is essential to examine how the
transported sunlit plasma is distributed. Through averaging the
hourly total electron content in solar-maximum winter, we
present complete distribution of polar ionospheric plasma and
find that the dayside plasma can be transported through cusp,
over polar cap, and eventually to the prevailing dawnside,
showing asymmetric distribution around magnetic midnight. The
negative interplanetary magnetic field B_y or B_z
component is favored for the plasma transportation from dayside
to the prevailing dawn sector. This provides direct evidence for
the plasma source of the dawnside high-density plasma structure.
The same corotating convection direction as convection at
auroral dawnside is responsible for the prevailing dawn sector
transportation. This finding is significant for forecasting
TOI/patches/blobs in conducting space weather in the polar
ionosphere.
BibTeX:
@article{2016JGRA..121.5626Y,
author = {Yang, Sheng-Gao and Zhang, Bei-Chen and Fang, Han-Xian and Kamide, Y. and Li, Chong-Yin and Liu, Jun-Ming and Zhang, Shun-Rong and Liu, Rui-Yuan and Zhang, Qing-He and Hu, Hong-Qiao},
title = {New evidence of dayside plasma transportation over the polar cap to the prevailing dawn sector in the polar upper atmosphere for solar-maximum winter},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2016},
volume = {121},
number = {6},
pages = {5626-5638},
doi = {https://doi.org/10.1002/2015JA022171}
}

Santamar\ia-Gómez, A., Gravelle, M., Dangendorf, S., Marcos, M., Spada, G. and Wöppelmann, G. Uncertainty of the 20th century sea-level rise due to vertical land motion errors 2017 Earth and Planetary Science Letters
Vol. 473, pp. 24-32
article DOI
Abstract: Assessing the vertical land motion (VLM) at tide gauges (TG) is crucial
to understanding global and regional mean sea-level changes
(SLC) over the last century. However, estimating VLM with
accuracy better than a few tenths of a millimeter per year is
not a trivial undertaking and many factors, including the
reference frame uncertainty, must be considered. Using a novel
reconstruction approach and updated geodetic VLM corrections, we
found the terrestrial reference frame and the estimated VLM
uncertainty may contribute to the global SLC rate error by
\pm 0.2 mmyr^-1. In addition, a spurious
global SLC acceleration may be introduced up to
\pm 4.8 texttimes10^-3 mmyr^-2.
Regional SLC rate and acceleration errors may be inflated by a
factor 3 compared to the global. The difference of VLM from two
independent Glacio-Isostatic Adjustment models introduces global
SLC rate and acceleration biases at the level of
\pm 0.1 mmyr^-1 and 2.8 texttimes10^-3
mmyr^-2, increasing up to 0.5 mm yr^-1 and 9
texttimes10^-3 mmyr^-2 for the regional SLC. Errors
in VLM corrections need to be budgeted when considering past and
future SLC scenarios.
BibTeX:
@article{2017E&PSL.473...24S,
author = {Santamar\ia-Gómez, Alvaro and Gravelle, Médéric and Dangendorf, Sönke and Marcos, Marta and Spada, Giorgio and Wöppelmann, Guy},
title = {Uncertainty of the 20th century sea-level rise due to vertical land motion errors},
journal = {Earth and Planetary Science Letters},
year = {2017},
volume = {473},
pages = {24-32},
doi = {https://doi.org/10.1016/j.epsl.2017.05.038}
}

Socquet, A., Déprez, A., Cotte, N., Maubant, L., Walpersdorf, A. and Bato, M.G. Present-day deformation in Europe, as seen by the EPOS-GNSS prototype solution in double difference, and first co- and post-seismic displacements associated with 2016 Amatrice and Norcia earthquakes (Italy) 2017 EGU General Assembly Conference Abstracts, pp. 17467  inproceedings
Abstract: We present here a new pan-European velocity field, obtained by
processing 500+ cGPS stations in double difference, in the
framework of the implementation phase of the European Plate
Observing System (EPOS) project. This prototype solution spans
the 2000-2016 period, and includes data from RING, NOA, RENAG
and European Permanent Network (EPN) cGPS netwprks. The data set
is first split into daily sub-networks (between 8 and 14 sub-
networks). The sub-networks consist in about 40 stations, with 2
overlapping stations. For each day and for each sub-network, the
GAMIT processing is conducted independently. Once each sub-
network achieves satisfactory results, a daily combination is
performed in order to produce SINEX files. The Chi square value
associated with the combination allows us to evaluate its
quality. Eventually, a multi year combination generates position
time series for each station. Each time series is visualized and
the jumps associated with material change (antenna or receiver)
are estimated and corrected. This procedure allows us to
generate daily solutions and position time series for all
stations. The associated interseismic'' velocity field has
then been estimated using a times series analysis using MIDAS
software, and compared to another independent estimate obtained
by Kalman filtering with globk software. In addition to this
velocity field we made a specific zoom on Italy and present a
strain rate map as well as time series showing co- and post-
seismic movements associated with the 2016 Amatrice and Norcia
earthquakes.
BibTeX:
@inproceedings{2017EGUGA..1917467S,
author = {Socquet, Anne and Déprez, Aline and Cotte, Nathalie and Maubant, Louise and Walpersdorf, Andrea and Bato, Mary Grace},
title = {Present-day deformation in Europe, as seen by the EPOS-GNSS prototype solution in double difference, and first co- and post-seismic displacements associated with 2016 Amatrice and Norcia earthquakes (Italy)},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2017},
pages = {17467}
}

Coster, A.J., Goncharenko, L., Zhang, S.-R., Erickson, P.J., Rideout, W. and Vierinen, J. GNSS Observations of Ionospheric Variations During the 21 August 2017 Solar Eclipse 2017 Geophysical Research Letter
Vol. 44(24), pp. 12,041-12,048
article DOI
Abstract: On 21 August 2017, during daytime hours, a total solar eclipse with a
narrow \sim160 km wide umbral shadow occurred
across the continental United States. Totality was observed from
the Oregon coast at \sim9:15 local standard time
(LST) (17:20 UT) to the South Carolina coast at
\sim13:27 LST (18:47 UT). A dense network of
Global Navigation Satellite Systems (GNSS) receivers was
utilized to produce total electron content (TEC) and
differential TEC. These data were analyzed for the latitudinal
and longitudinal response of the TEC and for the presence of
traveling ionospheric disturbances (TIDs) during eclipse
passage. A significant TEC depletion, in some cases greater than
60%, was observed associated with the eclipse shadow, exceeding
initial model predictions of 35%. Evidence of enhanced large-
scale TID activity was detected over the United States prior to
and following the large TEC depletion observed near the time of
totality. Signatures of enhanced TEC structures were observed
over the Rocky Mountain chain during the main period of TEC
depletion.
BibTeX:
@article{2017GeoRL..4412041C,
author = {Coster, Anthea J. and Goncharenko, Larisa and Zhang, Shun-Rong and Erickson, Philip J. and Rideout, William and Vierinen, Juha},
title = {GNSS Observations of Ionospheric Variations During the 21 August 2017 Solar Eclipse},
journal = {Geophysical Research Letter},
year = {2017},
volume = {44},
number = {24},
pages = {12,041-12,048},
doi = {https://doi.org/10.1002/2017GL075774}
}

Zhang, S.-R., Erickson, P.J., Goncharenko, L.P., Coster, A.J., Rideout, W. and Vierinen, J. Ionospheric Bow Waves and Perturbations Induced by the 21 August 2017 Solar Eclipse 2017 Geophysical Research Letter
Vol. 44(24), pp. 12,067-12,073
article DOI
Abstract: During solar eclipses, the Moon's shadow causes a large reduction in
atmospheric energy input, including not only the stratosphere
but also the thermosphere and ionosphere. The eclipse shadow has
a supersonic motion which is theoretically expected to generate
atmospheric bow waves, similar to a fast-moving river boat, with
waves starting in the lower atmosphere and propagating into the
ionosphere. However, previous geographically limited
observations have had difficulty detecting these weak waves
within the natural background atmospheric variability, and the
existence of eclipse-induced ionospheric waves and their
evolution in a complex coupling system remain controversial.
During the 21 August 2017 eclipse, high fidelity and wide
coverage ionospheric observations provided for the first time an
oversampled set of eclipse data, using a dense network of Global
\sim2,000 sites in North America. We show the
first unambiguous evidence of ionospheric bow waves as electron
content disturbances over central/eastern United States, with
\sim1 h duration, 300-400 km wavelength and 280
m/s phase speed emanating from and tailing the totality region.
We also identify large ionospheric perturbations moving at the
supersonic speed of the maximum solar obscuration which are too
fast to be associated with known gravity wave or large-scale
traveling ionospheric disturbance processes. This study reveals
complex interconnections between the Sun, Moon, and Earth's
neutral atmosphere and ionosphere and demonstrates persistent
coupling processes between different components of the Earth's
atmosphere, a topic of significant community interest.
BibTeX:
@article{2017GeoRL..4412067Z,
author = {Zhang, Shun-Rong and Erickson, Philip J. and Goncharenko, Larisa P. and Coster, Anthea J. and Rideout, William and Vierinen, Juha},
title = {Ionospheric Bow Waves and Perturbations Induced by the 21 August 2017 Solar Eclipse},
journal = {Geophysical Research Letter},
year = {2017},
volume = {44},
number = {24},
pages = {12,067-12,073},
doi = {https://doi.org/10.1002/2017GL076054}
}

Huba, J.D., Sazykin, S. and Coster, A. SAMI3-RCM simulation of the 17 March 2015 geomagnetic storm 2017 Journal of Geophysical Research (Space Physics)
Vol. 122(1), pp. 1246-1257
article DOI
Abstract: We present a self-consistent modeling study of the ionosphere-
plasmasphere system response to the 17 March 2015 geomagnetic
storm using the coupled SAMI3-RCM code. The novel feature of
this work is that we capture the important storm time dynamics
of the ionosphere on a global scale and its manifestation in the
plasmasphere. We find that the penetration electric fields
associated with the magnetic storm lead to a storm time enhanced
density in the low- to middle-latitude ionosphere. We compare
the modeled total electron content (TEC) with GPS-measured TEC
in the American sector. Additionally, we observe the development
of polar cap tongues of ionization'' and the formation of
subauroral plasma streams in the postsunset, premidnight sector,
and its impact on the plasmasphere. However, we did not see the
development of plasmaspheric plumes during this event which we
attribute to the long main phase of the storm
(\sim18 h).
BibTeX:
@article{2017JGRA..122.1246H,
author = {Huba, J. D. and Sazykin, S. and Coster, A.},
title = {SAMI3-RCM simulation of the 17 March 2015 geomagnetic storm},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2017},
volume = {122},
number = {1},
pages = {1246-1257},
doi = {https://doi.org/10.1002/2016JA023341}
}

Zhang, S.-R., Erickson, P.J., Zhang, Y., Wang, W., Huang, C., Coster, A.J., Holt, J.M., Foster, J.F., Sulzer, M. and Kerr, R. Observations of ion-neutral coupling associated with strong electrodynamic disturbances during the 2015 St. Patrick's Day storm 2017 Journal of Geophysical Research (Space Physics)
Vol. 122(1), pp. 1314-1337
article DOI
Abstract: We use incoherent scatter radar observations at Millstone Hill (MHO) and
Arecibo (AO) and topside ionosphere in situ Defense
Meteorological Satellite Program (DMSP) observations during the
great geomagnetic storm on 17-18 March 2015 to conduct a focused
study on ion-neutral coupling and storm time ionosphere and
thermosphere dynamics. Some of these observations were made
around the time of large ionospheric drifts within a subauroral
polarization stream (SAPS). During the storm main phase, we
identify multiple disturbance characteristics in the North
American late afternoon and dusk sector. (1) Strong subauroral
westward drifts occurred between 20 and 24 UT near MHO,
accompanied by a storm enhanced density plume passage over MHO
in the afternoon with a poleward/upward ion drift. The strongly
westward flow reached 2000 m/s speed near the poleward plume
edge. (2) Prompt penetration electric field signatures,
appearing as poleward/upward ion drifts on the dayside over both
MHO and AO, were consistent with DMSP vertical drift data and
contributed to plume development. (3) Meridional wind
equatorward surges occurred during daytime hours at MHO,
followed by 2-3 h period oscillations at both MHO and AO. The
zonal electric field at AO was strongly correlated with the wind
oscillation. (4) Large ion temperature enhancements as well as
50+ m/s upward ion drifts throughout the E and F regions were
observed during the SAPS period. These were presumably caused by
strong frictional heating due to large plasma drifts. The
heating effects appeared to drive significant atmospheric
upwelling, and corresponding ion upflow was also observed
briefly. This study highlights some of the important effects of
fast plasma transport as well as other disturbance dynamics on
ion-neutral coupling during a single intensification period
within a great geomagnetic storm.
BibTeX:
@article{2017JGRA..122.1314Z,
author = {Zhang, Shun-Rong and Erickson, Philip J. and Zhang, Yongliang and Wang, Wenbin and Huang, Chaosong and Coster, Anthea J. and Holt, John M. and Foster, John F. and Sulzer, Michael and Kerr, Robert},
title = {Observations of ion-neutral coupling associated with strong electrodynamic disturbances during the 2015 St. Patrick's Day storm},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2017},
volume = {122},
number = {1},
pages = {1314-1337},
doi = {https://doi.org/10.1002/2016JA023307}
}

Masoumi, S., McClusky, S., Koulali, A. and Tregoning, P. A directional model of tropospheric horizontal gradients in Global Positioning System and its application for particular weather scenarios 2017 Journal of Geophysical Research (Atmospheres)
Vol. 122(8), pp. 4401-4425
article DOI
Abstract: Improper modeling of horizontal tropospheric gradients in GPS analysis
induces errors in estimated parameters, with the largest impact
on heights and tropospheric zenith delays. The conventional two-
axis tilted plane model of horizontal gradients fails to provide
an accurate representation of tropospheric gradients under
weather conditions with asymmetric horizontal changes of
refractivity. A new parametrization of tropospheric gradients
whereby an arbitrary number of gradients are estimated as
discrete directional wedges is shown via simulations to
significantly improve the accuracy of recovered tropospheric
zenith delays in asymmetric gradient scenarios. In a case study
of an extreme rain event that occurred in September 2002 in
southern France, the new directional parametrization is able to
isolate the strong gradients in particular azimuths around the
GPS stations consistent with the V'' shape spatial pattern of
the observed precipitation. In another study of a network of GPS
stations in the Sierra Nevada region where highly asymmetric
tropospheric gradients are known to exist, the new directional
model significantly improves the repeatabilities of the stations
in asymmetric gradient situations while causing slightly
degraded repeatabilities for the stations in normal symmetric
gradient conditions. The average improvement over the entire
network is \sim31%, while the improvement for
one of the worst affected sites P631 is \sim49%
(from 8.5 mm to 4.3 mm) in terms of weighted root-mean-square
(WRMS) error and \sim82% (from -1.1 to -0.2) in
terms of skewness. At the same station, the use of the
directional model changes the estimates of zenith wet delay by
15 mm (\sim25%).
BibTeX:
@article{2017JGRD..122.4401M,
author = {Masoumi, Salim and McClusky, Simon and Koulali, Achraf and Tregoning, Paul},
title = {A directional model of tropospheric horizontal gradients in Global Positioning System and its application for particular weather scenarios},
journal = {Journal of Geophysical Research (Atmospheres)},
year = {2017},
volume = {122},
number = {8},
pages = {4401-4425},
doi = {https://doi.org/10.1002/2016JD026184}
}

Mathey, M., Walpersdorf, A., Baize, S., Sue, C., Doin, M.-P. and Potin, B. 3D deformation in the South-Western European Alps (Briançon region) revealed by 20 years of geodetic data 2018 EGU General Assembly Conference Abstracts, pp. 10415  inproceedings
Abstract: The overall Briançon region undergoes a moderate but steady
seismic activity with instrumental magnitudes up to Ml 5.0.
Previous studies pointed out that this area is characterized by
a great majority of extensional and dextral focal mechanisms,
along north-south to N160 oriented faults. Current works aim at
measuring and quantify the upper-crustal deformation in this
seismically active area, and to decipher the seismic part of the
deformation. A dense, local network of 30 GPS stations, covering
a 50 texttimes 60 km2 area has been temporarily surveyed in
1996, 2006, 2011 and 2016 by GPS, which represent one of the
longest repeated set of geodetic campaigns in the European Alps.
The combined analysis of the GPS temporary surveys over 20 years
with the continuous GPS measurements over 18 years from the
French RENAG network confirms horizontal velocity amplitudes
below 1 mm/year within the local network. The long observation
interval and the redundancy of the dense campaign network
measurement help to constrain a significant local deformation
pattern in the Briançon region, yielding an average E-W
extension of 22 \pm 8 nanostrain/year, coherent
with but more precise than previous results obtained before the
2016 measurements. The direction and amplitude of the geodetic
rate is both qualitatively and quantitatively coherent with the
deformation rate previously derived from 37 years of seismic
data (1970-2007). The next step of this project will be to
reassess the seismic stress/strain with an up to date database
all over the western Alps to better constrain the geodetic vs.
seismic deformation rates. A good vertical accuracy is also
revealed for the first time in the area by the long time span of
temporary GPS observations. We find that the accuracy of
vertical measures depends on the type of geodetic marker used,
namely screw marks and classical bolt marks, the first ones
being well coherent with permanent station velocities. Our new
integrated analysis (including the 2016 survey) confirms a
vertical average rate of 0.78 \pm 0.5 mm/yr over
10 years of measurement for the 19 screw marks. The uplift of
the core (so-called high chain) of the Alpine belt in this
extensional regime has already been observed on a larger scale
by permanent GPS stations, and is well discussed. Thanks to the
forced antenna centering, dense campaign networks are able to
provide significant constraints on geodynamic models of the
Alps, with a complementary spatial coverage with respect to
permanent GPS networks.
BibTeX:
@inproceedings{2018EGUGA..2010415M,
author = {Mathey, Marguerite and Walpersdorf, Andrea and Baize, Stéphane and Sue, Christian and Doin, Marie-Pierre and Potin, Bertrand},
title = {3D deformation in the South-Western European Alps (Briançon region) revealed by 20 years of geodetic data},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2018},
pages = {10415}
}

Jonah, O.F., Coster, A., Zhang, S., Goncharenko, L., Erickson, P.J., de Paula, E.R. and Kherani, E.A. TID Observations and Source Analysis During the 2017 Memorial Day Weekend Geomagnetic Storm Over North America 2018 Journal of Geophysical Research (Space Physics)
Vol. 123(10), pp. 8749-8765
article DOI
Abstract: We investigate ionospheric perturbations associated with traveling
ionospheric disturbance (TID) during the geomagnetic storm on
Memorial Day weekend (28 May) 2017. Results show the presence of
both equatorward propagating large-scale TIDs (LSTIDs) and
poleward propagating medium-scale TIDs. Equatorward moving TIDs
are connected with enhanced auroral activity owing to
geomagnetic storm conditions, while poleward TIDs are believed
to be induced by local atmospheric gravity wave sources
originating from convection activities near the West Coast of
North America. Measurements from magnetometers located in the
west, central, and east regions of North America are used to
evaluate energy inputs from the auroral belt, and these
observations confirm that equatorward LSTIDs are due to
geomagnetic disturbance. The observed LSTID waves were
characterized by some uncommon features, such as horizontal
wavefront stretching from coast to coast, aligned in the NW to
SE direction, and propagating to the southwest (equatorward)
direction during the storm main phase period. In contrast,
during the recovery phase and on other experimental control
days, the observed medium-scale TIDs were characterized with
relatively smaller wavelengths aligned in the NW to SE direction
and propagate primarily in the northeast (poleward) direction.
Our results also reveal that LSTID waves appear to travel faster
in the central continental region compared to LSTIDs in the
western and eastern regions.
BibTeX:
@article{2018JGRA..123.8749J,
author = {Jonah, O. F. and Coster, A. and Zhang, S. and Goncharenko, L. and Erickson, P. J. and de Paula, E. R. and Kherani, E. A.},
title = {TID Observations and Source Analysis During the 2017 Memorial Day Weekend Geomagnetic Storm Over North America},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2018},
volume = {123},
number = {10},
pages = {8749-8765},
doi = {https://doi.org/10.1029/2018JA025367}
}

Burrell, A.G., Perry, G.W., Yeoman, T.K., Milan, S.E. and Stoneback, R. Solar Influences on the Return Direction of High-Frequency Radar Backscatter 2018 Radio Science
Vol. 53(4), pp. 577-597
article DOI
Abstract: Coherent-scatter, high-frequency, phased-array radars create narrow
beams through the use of constructive and destructive
interference patterns. This formation method leads to the
creation of a secondary beam, or lobe, that is sent out behind
the radar. This study investigates the relative importance of
the beams in front of and behind the high-frequency radar
located in Hankasalmi, Finland, using observations taken over a
solar cycle, as well as coincident observations from Hankasalmi
and the Enhanced Polar Outflow Probe Radio Receiver Instrument.
These observations show that the relative strength of the front
and rear beams is frequency dependent, with the relative amount
of power sent to the front lobe increasing with increasing
frequency. At the range of frequencies used by Hankasalmi, both
front and rear beams are always present, though the main beam is
always stronger than the rear lobe. Because signals are always
transmitted to the front and rear of the radar, it is always
possible to receive backscatter from both return directions.
Examining the return direction as a function of local time,
season, and solar cycle shows that the dominant return direction
depends primarily on the local ionospheric structure. Diurnal
changes in plasma density typically cause an increase in the
amount of groundscatter returning from the rear lobe at night,
though the strength of this variation has a seasonal dependence.
Solar cycle variations are also seen in the groundscatter return
direction, modifying the existing local time and seasonal
variations.
BibTeX:
@article{2018RaSc...53..577B,
author = {Burrell, Angeline G. and Perry, Gareth W. and Yeoman, Timothy K. and Milan, Stephen E. and Stoneback, Russell},
title = {Solar Influences on the Return Direction of High-Frequency Radar Backscatter},
journal = {Radio Science},
year = {2018},
volume = {53},
number = {4},
pages = {577-597},
doi = {https://doi.org/10.1002/2017RS006512}
}

Aa, E., Ridley, A., Huang, W., Zou, S., Liu, S., Coster, A.J. and Zhang, S. An Ionosphere Specification Technique Based on Data Ingestion Algorithm and Empirical Orthogonal Function Analysis Method 2018 Space Weather
Vol. 16(9), pp. 1410-1423
article DOI
Abstract: A data ingestion method in reproducing ionospheric electron density and
total electron content (TEC) was developed to incorporate TEC
products from the Madrigal Database into the NeQuick 2 model.
The method is based on retrieving an appropriate global
distribution of effective ionization parameter (Az) to drive the
NeQuick 2 model, which can be implemented through minimizing the
difference between the measured and modeled TEC at each grid in
the local time-modified dip latitude coordinates. The
performance of this Madrigal TEC-driven-NeQuick 2 result is
validated through the comparison with various International
Global Navigation Satellite Systems Services global ionospheric
maps and ionosonde data. The validation results show that a
general accuracy improvement of 30-50% can be achieved after
data ingestion. In addition, the empirical orthogonal function
(EOF) analysis technique is used to construct a parameterized
time-varying global Az model. The quick convergence of EOF
decomposition makes it possible to use the first six EOF series
to represent over 90% of the total variances. The intrinsic
diurnal variation and spatial distribution in the original data
set can be well reflected by the constructed EOF base functions.
The associated EOF coefficients can be expressed as a set of
linear functions of F_10.7 and Ap indices, combined with a
series of trigonometric functions with annual/seasonal variation
components. The NeQuick TEC driven by EOF-modeled Az shows
10-15% improvement in accuracy over the standard ionosphere
correction algorithm in the Galileo navigation system. These
preliminary results demonstrate the effectiveness of the
combined data ingestion and EOF modeling technique in improving
the specifications of ionospheric density variations.
BibTeX:
@article{2018SpWea..16.1410A,
author = {Aa, Ercha and Ridley, Aaron and Huang, Wengeng and Zou, Shasha and Liu, Siqing and Coster, Anthea J. and Zhang, Shunrong},
title = {An Ionosphere Specification Technique Based on Data Ingestion Algorithm and Empirical Orthogonal Function Analysis Method},
journal = {Space Weather},
year = {2018},
volume = {16},
number = {9},
pages = {1410-1423},
doi = {https://doi.org/10.1029/2018SW001987}
}

Walpersdorf, A., Pinget, L., Vernant, P., Sue, C. and Deprez, A. Does Long-Term GPS in the Western Alps Finally Confirm Earthquake Mechanisms? 2018 Tectonics
Vol. 37(10), pp. 3721-3737
article DOI
Abstract: The availability of GPS survey data spanning 22 years, along with
several independent velocity solutions including up to 16 years
of permanent GPS data, presents a unique opportunity to search
for persistent (and thus reliable) deformation patterns in the
Western Alps, which in turn allow a reinterpretation of the
active tectonics of this region. While GPS velocities are still
too uncertain to be interpreted on an individual basis, the
analysis of range-perpendicular GPS velocity profiles clearly
highlights zones of extension in the center of the belt (15.3 to
3.1 nanostrain/year from north to south), with shortening in the
forelands. The contrasting geodetic deformation pattern is
coherent with earthquake focal mechanisms and related
strain/stress patterns over the entire Western Alps. The GPS
results finally provide a reliable and robust quantification of
the regional strain rates. The observed vertical motions of 2.0
to 0.5 mm/year of uplift from north to south in the core of the
Western Alps is interpreted to result from buoyancy forces
related to postglacial rebound, erosional unloading, and/or
viscosity anomalies in the crustal and lithospheric root.
Spatial decorrelation between vertical and horizontal
(seismicity related) deformation calls for a combination of
processes to explain the complex present-day dynamics of the
Western Alps.
BibTeX:
@article{2018Tecto..37.3721W,
author = {Walpersdorf, A. and Pinget, L. and Vernant, P. and Sue, C. and Deprez, A.},
title = {Does Long-Term GPS in the Western Alps Finally Confirm Earthquake Mechanisms?},
journal = {Tectonics},
year = {2018},
volume = {37},
number = {10},
pages = {3721-3737},
doi = {https://doi.org/10.1029/2018TC005054}
}

Rabin, M., Sue, C., Walpersdorf, A., Sakic, P., Albaric, J. and Fores, B. Present-Day Deformations of the Jura Arc Inferred by GPS Surveying and Earthquake Focal Mechanisms 2018 Tectonics
Vol. 37(10), pp. 3782-3804
article DOI
Abstract: This study presents a compilation of more than 40 years of
seismotectonic data, including 54 computed focal mechanisms,
combined with 15 years of GPS data coming from a dense network
of 35 permanent GPS stations within the Jura arc and its
vicinity. These data are compared to previous available
geomorphological, geophysical, and structural studies in order
to discuss the 3D distribution of the deformation within the
Jura arc. GPS data show coherent schemes in terms of velocities
and allowed to discriminate between two provinces (NE of the
belt and in its front/foreland). They also constrain a low but
significant overall strain tensor with a NNW-SSE shortening of
2.16 nanostrain/year associated with an ENE-WSW extension of
0.44 nanostrain/year. The seismotectonic approach is based on a
data set of 2,400 events and 54 focal mechanisms. Inversions of
the focal mechanisms both globally and in homogeneous sectors
highlight a general strike-slip deformation regime, with sigma1
oriented NW-SE and sigma3 oriented NE-SW. We discriminate two
different sectors in terms of basement/cover (un)coupling: (1)
potentially decoupled deformation between the basement and the
sedimentary cover in the NE part; and (2) coupled deformation in
the sedimentary cover and its basement in the Jura foreland.
BibTeX:
@article{2018Tecto..37.3782R,
author = {Rabin, Mickael and Sue, Christian and Walpersdorf, Andrea and Sakic, Pierre and Albaric, Julie and Fores, Benjamin},
title = {Present-Day Deformations of the Jura Arc Inferred by GPS Surveying and Earthquake Focal Mechanisms},
journal = {Tectonics},
year = {2018},
volume = {37},
number = {10},
pages = {3782-3804},
doi = {https://doi.org/10.1029/2018TC005047}
}

Koval, A., Chen, Y., Tsugawa, T., Otsuka, Y., Shinbori, A., Nishioka, M., Brazhenko, A., Stanislavsky, A., Konovalenko, A., Zhang, Q.-H., Monstein, C. and Gorgutsa, R. Direct Observations of Traveling Ionospheric Disturbances as Focusers of Solar Radiation: Spectral Caustics 2019 Astrophysical Journal
Vol. 877(2), pp. 98
article DOI
Abstract: The solar radiation focusing effect is related to the specific
phenomenon of propagation of the Sun-emitted HF and VHF waves
through terrestrial ionosphere. This natural effect is observed
with ground-based radio instruments running within the 10-200
MHz range as distinctive patterns—the spectral
caustics (SCs)—on the solar dynamic spectra. It has
been suggested that SCs are associated with medium-scale
traveling ionospheric disturbances (MSTIDs). In this paper, we
present the first direct observations of SCs induced by MSTIDs,
using solar dynamic spectra with SCs obtained by different
European radio telescopes on 2014 January 8 and simultaneous
two-dimensional detrended total electron content (dTEC) maps
over Europe. Spatial examination of dTEC maps as well as precise
timing analysis of the maps and the dynamic spectra have been
performed. First, we found several pairs of one-to-one (TID-SC)
correspondences. The study provides strong observational
evidence supporting the suggestion that MSTIDs are the cause of
SCs.
BibTeX:
@article{2019ApJ...877...98K,
author = {Koval, Artem and Chen, Yao and Tsugawa, Takuya and Otsuka, Yuichi and Shinbori, Atsuki and Nishioka, Michi and Brazhenko, Anatoliy and Stanislavsky, Aleksander and Konovalenko, Aleksander and Zhang, Qing-He and Monstein, Christian and Gorgutsa, Roman},
title = {Direct Observations of Traveling Ionospheric Disturbances as Focusers of Solar Radiation: Spectral Caustics},
journal = {Astrophysical Journal},
year = {2019},
volume = {877},
number = {2},
pages = {98},
doi = {https://doi.org/10.3847/1538-4357/ab1b52}
}

Mathey, M., Walpersdorf, A., Baize, S., Doin, M.-P. and Sue, C. Slow deformation in the Briançon area (South-Western Alps, France) : can we localize it on active fault(s) ? 2019 EGU General Assembly Conference Abstracts, pp. 12614  inproceedings
Abstract: The Western Alps show persistent seismicity and deformation despite the
end of the orogenesis. The first stations of the RENAG permanent
GNSS network were thus installed in the French Alps since the
end of the 1990s. Moreover, three temporary surveys took place
in 1996, 2006 and 2011 in the Briançon area, 50x50
km^2 wide, in the South-Western French Alps, where a steady
moderate seismic activity along the Briançon seismic arc
is observed. The horizontal velocity field computed from these
first three surveys showed an east-west extension in the
network, compatible in amplitude and in orientation with the
seismic deformation of the area. A fourth campaign was led in
2016, yielding 20 years of observation span. The measures may
now reach a sufficient accuracy to assess if the extension found
within the Briançon network is localized on any particular
tectonic feature. Several faults in this area indeed showed
recent activity in normal faulting. Assessing the localization
of the deformation may lead to better understand the origin and
processes of the present-day deformation of the Alpine belt. To
address this issue, the present study aimed at increasing the
resolution of both the velocity and the strain field over the
network, by exploiting the long measurement span and the
exceptional redundancy of our campaign measurements : 1) A
robust velocity field was computed from the combination of the
different campaign and permanent data. A single strain tensor
was then derived, revealing 20\pm2 nanostrain/yr,
which is consistent with previous studies, and also more
accurate. 2) Two inversion methods were then compared to assess
the distribution of the deformation over the area. Despite their
coherence on the orientation of the deformation, the size of the
network compared to the small amplitude of the signal did not
enable us to derive significant values of strain over the width
of the grid cells. 3) We then tried to localize the deformation
by fitting a model to a GPS velocity profile perpendicular to
the faults. Despite the high uncertainties on the GPS
velocities, a two fault model seems to be the best fit to the
data. The localization of the potential faults being the best
constrained parameter in this forward model, we used it as
apriori information in a block modeling in order to compute
fault slip rates as the velocities at the interface of the
blocks. The velocities on the interfaces are found to be
strongly dependent on the model parameters but remain below 1
mm/yr. Thanks to the unusual density of the network and long
time span of its instrumentation, we were able to increase the
accuracy of the deformation pattern observed through the
Briançon area. Our results suggest that the extension is
localized on two nearby tectonic features, even if the fault
parameters retrieved from our models differ slightly from
geological and seismotectonics clues. These results encourage us
to believe that the next survey will add sufficient signal-to-
noise ratio to achieve the data convergence towards the regional
tectonic signal.
BibTeX:
@inproceedings{2019EGUGA..2112614M,
author = {Mathey, Marguerite and Walpersdorf, Andrea and Baize, Stéphane and Doin, Marie-Pierre and Sue, Christian},
title = {Slow deformation in the Briançon area (South-Western Alps, France) : can we localize it on active fault(s) ?},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2019},
pages = {12614}
}

Sternai, P., Sue, C., Husson, L., Serpelloni, E., Becker, T.W., Willett, S.D., Faccenna, C., Di Giulio, A., Spada, G., Jolivet, L., Valla, P., Petit, C., Nocquet, J.-M., Walpersdorf, A. and Castelltort, S. Present-day uplift of the European Alps: Evaluating mechanisms and models of their relative contributions 2019 Earth Science Reviews
Vol. 190, pp. 589-604
article DOI
Abstract: Recent measurements of surface vertical displacements of the European
Alps show a correlation between vertical velocities and
topographic features, with widespread uplift at rates of up to
2-2.5 mm/a in the North-Western and Central Alps, and 1 mm/a
across a continuous region from the Eastern to the South-Western
Alps. Such a rock uplift rate pattern is at odds with the
horizontal velocity field, characterized by shortening and
crustal thickening in the Eastern Alps and very limited
deformation in the Central and Western Alps. Proposed mechanisms
of rock uplift rate include isostatic response to the last
deglaciation, long-term erosion, detachment of the Western
Alpine slab, as well as lithospheric and surface deflection due
to mantle convection. Here, we assess previous work and present
new estimates of the contributions from these mechanisms. Given
the large range of model estimates, the isostatic adjustment to
deglaciation and erosion are sufficient to explain the full
observed rate of uplift in the Eastern Alps, which, if correct,
would preclude a contribution from horizontal shortening and
crustal thickening. Alternatively, uplift is a partitioned
response to a range of mechanisms. In the Central and Western
Alps, the lithospheric adjustment to deglaciation and erosion
likely accounts for roughly half of the rock uplift rate, which
points to a noticeable contribution by mantle-related processes
such as detachment of the European slab and/or asthenospheric
upwelling. While it is difficult to independently constrain the
patterns and magnitude of mantle contributions to ongoing Alpine
vertical displacements at present, future data should provide
additional insights. Regardless, interacting tectonic and
surface mass redistribution processes, rather than an individual
forcing, best explain ongoing Alpine elevation changes.
BibTeX:
@article{2019ESRv..190..589S,
author = {Sternai, Pietro and Sue, Christian and Husson, Laurent and Serpelloni, Enrico and Becker, Thorsten W. and Willett, Sean D. and Faccenna, Claudio and Di Giulio, Andrea and Spada, Giorgio and Jolivet, Laurent and Valla, Pierre and Petit, Carole and Nocquet, Jean-Mathieu and Walpersdorf, Andrea and Castelltort, Sébastien},
title = {Present-day uplift of the European Alps: Evaluating mechanisms and models of their relative contributions},
journal = {Earth Science Reviews},
year = {2019},
volume = {190},
pages = {589-604},
doi = {https://doi.org/10.1016/j.earscirev.2019.01.005}
}

David, M., Sojka, J.J., Schunk, R.W. and Coster, A.J. Hemispherical Shifted Symmetry in Polar Cap Patch Occurrence: A Survey of GPS TEC Maps From 2015-2018 2019 Geophysical Research Letter
Vol. 46(19), pp. 10,726-10,734
article DOI
Abstract: Much theoretical and observational work has been devoted to studying the
occurrence of F region polar cap patches in the Northern
Hemisphere; considerably less work has been applied to the
Southern Hemisphere. In recent years, the Madrigal database of
mappings of total electron content (TEC) has improved in
Southern Hemisphere coverage, to the point that we can now carry
out a study of patch frequency and occurrence. We find that
Southern Hemisphere patch occurrence is very similar to that of
the Northern Hemisphere with a half-year offset, plus an offset
in universal time of approximately 12 hr. This is further
supported by running an ionospheric model for both hemispheres
and applying the same patch-to-background technique. Further, we
present a simple physical mechanism involving a sunlit dayside
plasma source concurrent with a dark polar cap, which yields a
patch-to-background pattern very much like that seen in the TEC
mappings for both hemispheres.
BibTeX:
@article{2019GeoRL..4610726D,
author = {David, M. and Sojka, J. J. and Schunk, R. W. and Coster, A. J.},
title = {Hemispherical Shifted Symmetry in Polar Cap Patch Occurrence: A Survey of GPS TEC Maps From 2015-2018},
journal = {Geophysical Research Letter},
year = {2019},
volume = {46},
number = {19},
pages = {10,726-10,734},
doi = {https://doi.org/10.1029/2019GL083952}
}

Guo, M., Xu, N., Feng, J. and Deng, Z. A prolonged pattern of the ionospheric depletion in the south of the 21 August 2017 solar eclipse path 2019 Journal of Atmospheric and Solar-Terrestrial Physics
Vol. 199, pp. 105208
article DOI
Abstract: During the American solar eclipse on 21 August 2017, the GNSS network
was applied to record the ionospheric responses. Following the
lunar shadow, the TEC depletion emerged over the eclipse path.
After the eclipse end, the depletion in the north gradually
disappeared and then the TEC enhancement emerged. The depletion
in the south has continued for a long time. A sharp area between
the enhancement and depletion regions appeared at
27textdegreeN latitude. Moreover, the depletion region were
moving to south with larger and larger TEC decline after the
eclipse maximum. The TEC over four selected places with same
latitude and different eclipse obscurations is presented.
Interestingly, the recovery periods of these TEC values are
similar. The f_oF2 and h_mF2 in the enhancement and
depletion regions displayed very different variation tendency.
The eclipse-induced thermospheric winds are considered to
further reduce the TEC after the eclipse. The formation of the
sharp area in TEC may be related to the fountain effect.
BibTeX:
@article{2019JASTP.19905208G,
author = {Guo, Ming and Xu, Na and Feng, Jian and Deng, Zhongxin},
title = {A prolonged pattern of the ionospheric depletion in the south of the 21 August 2017 solar eclipse path},
journal = {Journal of Atmospheric and Solar-Terrestrial Physics},
year = {2019},
volume = {199},
pages = {105208},
doi = {https://doi.org/10.1016/j.jastp.2020.105208}
}

Lyons, L.R., Nishimura, Y., Zhang, S.R., Coster, A.J., Bhatt, A., Kendall, E. and Deng, Y. Identification of Auroral Zone Activity Driving Large-Scale Traveling Ionospheric Disturbances 2019 Journal of Geophysical Research (Space Physics)
Vol. 124(1), pp. 700-714
article DOI
Abstract: We have used all-sky imaging to relate different types of auroral oval
disturbances to large-scale traveling ionospheric disturbances
(LSTIDs). We selected eight nights with good all-sky imaging and
Global Positioning System total electron content coverage,
including five non-storm time periods with isolated initiations
of geomagnetic activity and three storm main phase periods with
continuous activity. Periods with LSTIDs generally started and
stopped with initiation and cessation of activity. We found
evidence that individual LSTIDs often show 1-1 correspondence
with identifiable auroral disturbances, disturbances either
being related to a substorm onset or to auroral streamers
without a substorm. Since substorm ground magnetic depressions
are directly related to the electric fields and electron
precipitation of auroral streamers, we hypothesize that
streamers may be the primary drivers of individual nightside
LSTIDs with or without a substorm. Additionally, we found
evidence that (1) LSTIDs detection is more likely near the
longitude range of the initiating disturbance than further away,
(2) the orientation of LSTID phase fronts depends on location
relative to disturbance longitude, and (3) disturbance
ionospheric current and magnetic latitude may influence whether
a given disturbance leads to a detectable LSTID. Numerous LSTIDs
(10 to 12 over 7- to 8-hr periods) were detected during
southward interplanetary magnetic field periods of coronal mass
ejection storm main phases, the vast majority reflecting
streamers in the absence of substorms. Less LSTIDs were seen
during the one examined high-speed-stream storm. We have also
found evidence that omega band disturbances may drive
interesting TIDs that are distinct from the LSTIDs driven by the
substorm and streamer disturbances.
BibTeX:
@article{2019JGRA..124..700L,
author = {Lyons, L. R. and Nishimura, Y. and Zhang, S. -R. and Coster, A. J. and Bhatt, A. and Kendall, E. and Deng, Y.},
title = {Identification of Auroral Zone Activity Driving Large-Scale Traveling Ionospheric Disturbances},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2019},
volume = {124},
number = {1},
pages = {700-714},
doi = {https://doi.org/10.1029/2018JA025980}
}

Zhang, S.-R., Coster, A.J., Erickson, P.J., Goncharenko, L.P., Rideout, W. and Vierinen, J. Traveling Ionospheric Disturbances and Ionospheric Perturbations Associated With Solar Flares in September 2017 2019 Journal of Geophysical Research (Space Physics)
Vol. 124(7), pp. 5894-5917
article DOI
Abstract: Solar flares provide strong impulsive radiation and energy injection to
the sunlit upper atmosphere. The impact on the ionosphere is
immense in spatial scale, and therefore, it is not immediately
evident if dramatically elevated neutral heating can lead to
excitation of acoustic gravity waves. Using primary observations
from Global Navigation Satellite System differential TEC (total
electron content) over the continental United States, this paper
presents postflare ionospheric observations associated with
three X-class flares on 6, 7, and 10 September 2017. Postflare
ionospheric changes had two significant morphological
characteristics: (1) A few minutes after the X9.3 flare peak on
6 September, clear traveling ionospheric disturbance (TID)
fronts emanated near the sunrise terminator with alignment
parallel to its direction—TIDs propagated
predominantly eastward into the dayside with a 150 m/s phase
speed and a \sim30-min period; (2) synchronized
differential TEC oscillations over continental United States
with \sim60-min periodicity and damping amplitude
over time, following all three X-class flares. Postflare
ionospheric oscillation spectra exhibited significantly enhanced
amplitudes and changes of periodicities (including the
appearance of the 60-min oscillations). The Millstone Hill
incoherent scatter radar observed large ionospheric up-welling
occurring nearly simultaneously as detected TIDs at the X9.3
flare peak, with up to 80 m/s enhancements in vertical drift at
500 km lasting for \sim30 min. Results suggest
that significant solar flare heating and associated dynamical
effects may be an important factor in TID/acoustic gravity wave
excitation.
BibTeX:
@article{2019JGRA..124.5894Z,
author = {Zhang, Shun-Rong and Coster, Anthea J. and Erickson, Philip J. and Goncharenko, Larisa P. and Rideout, William and Vierinen, Juha},
title = {Traveling Ionospheric Disturbances and Ionospheric Perturbations Associated With Solar Flares in September 2017},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2019},
volume = {124},
number = {7},
pages = {5894-5917},
doi = {https://doi.org/10.1029/2019JA026585}
}

Xiong, C., Lühr, H. and Yamazaki, Y. An Opposite Response of the Low-Latitude Ionosphere at Asian and American Sectors During Storm Recovery Phases: Drivers From Below or Above 2019 Journal of Geophysical Research (Space Physics)
Vol. 124(7), pp. 6266-6280
article DOI
Abstract: In this study, we focus on the recovery phase of a geomagnetic storm
that happened on 6-11 September 2017. The ground-based total
electron content data, as well as the F region in situ electron
density, measured by the Swarm satellites show an interesting
feature, revealing at low and equatorial latitudes on the
dayside ionosphere prominent positive and negative responses at
the Asian and American longitudinal sectors, respectively. The
global distribution of thermospheric O/N_2 ratio measured by
global ultraviolet imager on board the Thermosphere, Ionosphere,
Mesosphere Energetics and Dynamics satellite cannot well explain
such longitudinally opposite response of the ionosphere.
Comparison between the equatorial electrojet variations from
stations at Huancayo in Peru and Davao in the Philippines
suggests that the longitudinally opposite ionospheric response
should be closely associated with the interplay of E region
electrodynamics. By further applying nonmigrating tidal analysis
to the ground-based total electron content data, we find that
the diurnal tidal components, D0 and DW2, as well as the
semidiurnal component SW1, are clearly enhanced over prestorm
days and persist into the early recovery phase, indicating the
possibility of lower atmospheric forcing contributing to the
longitudinally opposite response of the ionosphere on 9-11
September 2017.
BibTeX:
@article{2019JGRA..124.6266X,
author = {Xiong, Chao and Lühr, Hermann and Yamazaki, Yosuke},
title = {An Opposite Response of the Low-Latitude Ionosphere at Asian and American Sectors During Storm Recovery Phases: Drivers From Below or Above},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2019},
volume = {124},
number = {7},
pages = {6266-6280},
doi = {https://doi.org/10.1029/2019JA026917}
}

Liu, L., Le, H., Chen, Y., Zhang, R., Wan, W. and Zhang, S.-R. New Aspects of the Ionospheric Behavior Over Millstone Hill During the 30-Day Incoherent Scatter Radar Experiment in October 2002 2019 Journal of Geophysical Research (Space Physics)
Vol. 124(7), pp. 6288-6295
article DOI
Abstract: The geomagnetic storm-driven ionospheric changes and the involved
processes are interesting and challenging topics in
understanding and predicting the ionosphere. In this study we
investigate the response of the ionosphere to geomagnetic
disturbances during the 30-day incoherent scatter radar
measurements conducted at Millstone Hill (42.6textdegreeN,
71.5textdegreeW) from 4 October to 4 November 2002. During
geomagnetically disturbed periods, while the peak electron
density of the F2 layer (NmF2) and total electron content
deviate remarkably from the quiet time ones in a similar way,
the incoherent scatter radar measurements reveal that the
changes in electron density are frequently different between low
and high altitudes. The electron density is significantly
depleted at low altitudes; however, at topside it either changes
slightly or sometime is enhanced. The enhanced vertical scale
height around 600 km under geomagnetically active conditions
implies that the topside electron density profiles become much
steeper. The increase in the peak height of F2 layer (hmF2)
indicates the upward motions under the action of the storm-
driven dynamic processes. Further, sometimes strong differences
are shown in total electron content between Millstone Hill and
longitude 100textdegreeW. The competing contributions from
dynamic processes and disturbance composition to the storm-time
ionospheric changes over Millstone Hill are indicated in the
different responses in electron density at the bottomside and
topside of the ionosphere.
BibTeX:
@article{2019JGRA..124.6288L,
author = {Liu, Libo and Le, Huijun and Chen, Yiding and Zhang, Ruilong and Wan, Weixing and Zhang, Shun-Rong},
title = {New Aspects of the Ionospheric Behavior Over Millstone Hill During the 30-Day Incoherent Scatter Radar Experiment in October 2002},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2019},
volume = {124},
number = {7},
pages = {6288-6295},
doi = {https://doi.org/10.1029/2019JA026806}
}

Aa, E., Zou, S., Ridley, A., Zhang, S., Coster, A.J., Erickson, P.J., Liu, S. and Ren, J. Merging of Storm Time Midlatitude Traveling Ionospheric Disturbances and Equatorial Plasma Bubbles 2019 Space Weather
Vol. 17(2), pp. 285-298
article DOI
Abstract: Postsunset midlatitude traveling ionospheric disturbances (TIDs) and
equatorial plasma bubbles (EPBs) were simultaneously observed
over American sector during the geomagnetic storm on 8 September
2017. The characteristics of TIDs are analyzed by using a
combination of the Millstone Hill incoherent scatter radar data
and 2-D detrended total electron content (TEC) from ground-based
Global Navigation Satellite System receivers. The main results
associated with EPBs are as follows: (1) stream-like structures
of TEC depletion occurred simultaneously at geomagnetically
conjugate points, (2) poleward extension of the TEC
irregularities/depletions along the magnetic field lines, (3)
severe equatorial and midlatitude electron density (Ne) bite
outs observed by Defense Meteorological Satellite Program and
Swarm satellites, and (4) enhancements of ionosphere F layer
virtual height and vertical drifts observed by equatorial
ionosondes near the EPBs initiation region. The stream-like TEC
depletions reached 46textdegree magnetic latitudes that map
to an apex altitude of 6,800 km over the magnetic equator using
International Geomagnetic Reference Field. The formation of this
extended density depletion structure is suggested to be due to
the merging between the altitudinal/latitudinal extension of
EPBs driven by strong prompt penetration electric field and
midlatitude TIDs. Moreover, the poleward portion of the
depletion/irregularity drifted westward and reached the
equatorward boundary of the ionospheric main trough. This
westward drift occurred at the same time as the sudden expansion
of the convection pattern and could be attributed to the strong
returning westward flow near the subauroral polarization stream
region. Other possible mechanisms for the westward tilt are also
discussed.
BibTeX:
@article{2019SpWea..17..285A,
author = {Aa, Ercha and Zou, Shasha and Ridley, Aaron and Zhang, Shunrong and Coster, Anthea J. and Erickson, Philip J. and Liu, Siqing and Ren, Jiaen},
title = {Merging of Storm Time Midlatitude Traveling Ionospheric Disturbances and Equatorial Plasma Bubbles},
journal = {Space Weather},
year = {2019},
volume = {17},
number = {2},
pages = {285-298},
doi = {https://doi.org/10.1029/2018SW002101}
}

Obana, Y., Maruyama, N., Shinbori, A., Hashimoto, K.K., Fedrizzi, M., Nosé, M., Otsuka, Y., Nishitani, N., Hori, T., Kumamoto, A., Tsuchiya, F., Matsuda, S., Matsuoka, A., Kasahara, Y., Yoshikawa, A., Miyoshi, Y. and Shinohara, I. Response of the Ionosphere-Plasmasphere Coupling to the September 2017 Storm: What Erodes the Plasmasphere so Severely? 2019 Space Weather
Vol. 17(6), pp. 861-876
article DOI
Abstract: We report an extreme erosion of the plasmasphere arising from the
September 2017 storm. The cold electron density is identified
from the upper limit frequency of upper hybrid resonance waves
observed by the Plasma Wave Experiment instrument onboard the
Exploration of energization and Radiation in Geospace/Arase
satellite. The electron density profiles reveal that the
plasmasphere was severely eroded during the recovery phase of
the storm and the plasmapause was located at L = 1.6-1.7 at 23
UT 8 September 2017. This is the first report of deep erosion of
the plasmasphere (L_PP lt 2) with the in situ observation
of the electron density. The degree of the severity is much more
than what is expected from the relatively moderate value of the
SYM-H minimum (-146 nT). We attempt to find a possible
explanation for the observed severe depletion by using both
observational evidence and numerical simulations. Our results
suggest that the middle latitude electric field had penetrated
from the high-latitude storm time convection for several hours.
Such an unusually long-lasting penetration event can cause this
observed degree of severity.
BibTeX:
@article{2019SpWea..17..861O,
author = {Obana, Yuki and Maruyama, Naomi and Shinbori, Atsuki and Hashimoto, Kumiko K. and Fedrizzi, Mariangel and Nosé, Masahito and Otsuka, Yuichi and Nishitani, Nozomu and Hori, Tomoaki and Kumamoto, Atsushi and Tsuchiya, Fuminori and Matsuda, Shoya and Matsuoka, Ayako and Kasahara, Yoshiya and Yoshikawa, Akimasa and Miyoshi, Yoshizumi and Shinohara, Iku},
title = {Response of the Ionosphere-Plasmasphere Coupling to the September 2017 Storm: What Erodes the Plasmasphere so Severely?},
journal = {Space Weather},
year = {2019},
volume = {17},
number = {6},
pages = {861-876},
doi = {https://doi.org/10.1029/2019SW002168}
}

Fæhn Follestad, A., Clausen, L.B.N., Thomas, E.G., Jin, Y. and Coster, A. Polar Cap Patch Prediction in the Expanding Contracting Polar Cap Paradigm 2019 Space Weather
Vol. 17(11), pp. 1570-1583
article DOI
Abstract: Space weather can cause serious disturbances of global navigation
satellite systems (GNSS) used for positioning and navigation
purposes. This paper describes a new method to forecast space
weather disturbances on GNSS at high latitudes, in which we
describe the formation and propagation of polar cap patches and
predict their arrival at the nightside auroral oval. The space
weather prediction model builds on the expanding/contracting
polar cap (ECPC) paradigm and total electron content (TEC)
observations from the Global Positioning System (GPS) network.
The input parameter is satellite observations of the
interplanetary magnetic field at the first Lagrange point. To
validate our prediction model, we perform a case study in which
we compare the results from our prediction model to observations
from the GPS TEC data from the MIT's Madrigal database,
convection data from Super Dual Auroral radar network, and
scintillation data from Svalbard. Our results show that the ECPC
paradigm describes the polar cap patch motion well and can be
used to predict scintillations of GPS signals at high latitudes.
BibTeX:
@article{2019SpWea..17.1570F,
author = {Fæhn Follestad, A. and Clausen, L. B. N. and Thomas, E. G. and Jin, Y. and Coster, A.},
title = {Polar Cap Patch Prediction in the Expanding Contracting Polar Cap Paradigm},
journal = {Space Weather},
year = {2019},
volume = {17},
number = {11},
pages = {1570-1583},
doi = {https://doi.org/10.1029/2019SW002276}
}

Zhang, S.-R., Erickson, P.J., Coster, A.J., Rideout, W., Vierinen, J., Jonah, O. and Goncharenko, L.P. Subauroral and Polar Traveling Ionospheric Disturbances During the 7-9 September 2017 Storms 2019 Space Weather
Vol. 17(12), pp. 1748-1764
article DOI
Abstract: This study provides new scenarios for storm time traveling ionospheric
disturbance excitation and subsequent propagation at subauroral
and polar latitudes. We used ground-based total electron content
observations from Global Navigation Satellite System receivers
combined with wide field, subauroral ionospheric plasma
parameters measured with the Millstone Hill Incoherent Scatter
Radar during strong September 2017 geospace storms. Observations
provide the first evidence of significant influences on
traveling ionospheric disturbance (TID) propagation and
excitation caused by the presence of large subauroral
polarization stream flow channels. Simultaneous large- and
medium-scale TIDs evolved during the event in a broad subauroral
and midlatitude area near dusk. Similar concurrent TIDs occurred
near dawn sectors as well during a period of sustained southward
Bz. Medium-scale TIDs at subauroral and midlatitudes had wave
fronts aligned northwest-southeast near dusk, and northeast-
southwest near dawn. These wave fronts were highly correlated
with the direction of storm time large zonal plasma drift
enhancements at these latitudes. At high latitudes, unexpected,
predominant, and persistent storm time TIDs were identified with
2000+ km zonal wave fronts and 15% total electron content
perturbation amplitudes, moving in transpolar propagation
pathways from the dayside into the nightside. This propagation
direction in the polar region was opposite to the normal
assumption that TIDs originated in the nightside auroral region.
Results suggest that significant dayside sources, such as cusp
regions, can be efficient in generating transpolar TIDs during
geospace storm intervals.
BibTeX:
@article{2019SpWea..17.1748Z,
author = {Zhang, Shun-Rong and Erickson, Philip J. and Coster, Anthea J. and Rideout, William and Vierinen, Juha and Jonah, Olusegun and Goncharenko, Larisa P.},
title = {Subauroral and Polar Traveling Ionospheric Disturbances During the 7-9 September 2017 Storms},
journal = {Space Weather},
year = {2019},
volume = {17},
number = {12},
pages = {1748-1764},
doi = {https://doi.org/10.1029/2019SW002325}
}

Gimbert, F., Nanni, U., Roux, P., Helmstetter, A., Garambois, S., Lecointre, A., Walpersdorf, A., Jourdain, B., Langlais, M., Larman, O., Lindner, F., Sergeant, A., Vincent, C. and Walter, F. The RESOLVE project: a multi-physics experiment with a temporary dense seismic array on the Argentière Glacier, French Alps 2020 arXiv e-prints, pp. arXiv:2009.06321  article
Abstract: Recent work in the field of cryo-seismology demonstrates that high
frequency (gt1 Hz) waves provide key constraints on a wide
range of glacier processes such as basal friction, surface
crevassing or subglacial water flow. Establishing quantitative
links between the seismic signal and the processes of interest
however requires detailed characterization of the wavefield,
which at the high frequencies of interest necessitates the
deployment of large and particularly dense seismic arrays.
Although dense seismic array monitoring has recently become
routine in geophysics, its application to glaciated environments
has yet remained limited. Here we present a dense seismic array
experiment made of 98 3-component seismic stations continuously
recording during 35 days in early spring on the Argentière
Glacier, French Alps. The seismic dataset is supplemented by a
wide range of complementary observations obtained from ground
penetrating radar, drone imagery, GNSS positioning and in-situ
instrumentation of basal glacier sliding velocities and
subglacial water discharge. Through applying multiple processing
techniques including event detection from template matching and
systematic beamforming, we demonstrate that the present dataset
provides enhanced spatial resolution on basal stick slip and
englacial fracturing sources as well as novel constraints on
heterogeneous nature of the noise field generated by subglacial
water flow and on the link between crevasse properties and
englacial seismic velocities. We finally outline in which ways
further work using this dataset could help tackle key remaining
questions in the field.
BibTeX:
@article{2020arXiv200906321G,
author = {Gimbert, Florent and Nanni, Ugo and Roux, Philippe and Helmstetter, Agnés and Garambois, Stéphane and Lecointre, Albanne and Walpersdorf, Andrea and Jourdain, Bruno and Langlais, Mickael and Larman, Olivier and Lindner, Fabian and Sergeant, Amandine and Vincent, Christian and Walter, Fabian},
title = {The RESOLVE project: a multi-physics experiment with a temporary dense seismic array on the Argentière Glacier, French Alps},
journal = {arXiv e-prints},
year = {2020},
pages = {arXiv:2009.06321}
}

Kreemer, C., Blewitt, G. and Davis, P.M. Geodetic evidence for a buoyant mantle plume beneath the Eifel volcanic area, NW Europe 2020 Geophysical Journal International
Vol. 222(2), pp. 1316-1332
article DOI
Abstract: The volcanism of the Eifel volcanic field (EVF), in west-central
Germany, is often considered an example of hotspot volcanism
given its geochemical signature and the putative mantle plume
imaged underneath. EVF's setting in a stable continental area
provides a rare natural laboratory to image surface deformation
and test the hypothesis of there being a thermally buoyant
plume. Here we use Global Positioning System (GPS) data to
robustly image vertical land motion (VLM) and horizontal strain
rates over most of intraplate Europe. We find a spatially
coherent positive VLM anomaly over an area much larger than the
EVF and with a maximum uplift of \sim1 mm
yr^-1 at the EVF (when corrected for glacial isostatic
adjustment). This rate is considerably higher than averaged over
the Late-Quaternary. Over the same area that uplifts, we find
significant horizontal extension surrounded by a radial pattern
of shortening, a superposition that strongly suggests a common
dynamic cause. Besides the Eifel, no other area in NW Europe
shows significant positive VLM coupled with extensional strain
rates, except for the much broader region of glacial isostatic
adjustment. We refer to this 3-D deformation anomaly as the
Eifel Anomaly. We also find an extensional strain rate anomaly
near the Massif Central volcanic field surrounded by radial
shortening, but we do not detect a significant positive VLM
signal there. The fact that the Eifel Anomaly is located above
the Eifel plume suggests that the plume causes the anomaly.
Indeed, we show that buoyancy forces induced by the plume at the
bottom of the lithosphere can explain this remarkable surface
deformation. Plume-induced deformation can also explain the
relatively high rate of regional seismicity, particularly along
the Lower Rhine Embayment.
BibTeX:
@article{2020GeoJI.222.1316K,
author = {Kreemer, Corné and Blewitt, Geoffrey and Davis, Paul M.},
title = {Geodetic evidence for a buoyant mantle plume beneath the Eifel volcanic area, NW Europe},
journal = {Geophysical Journal International},
year = {2020},
volume = {222},
number = {2},
pages = {1316-1332},
doi = {https://doi.org/10.1093/gji/ggaa227}
}

Mathey, M., Walpersdorf, A., Sue, C., Baize, S. and Deprez, A. Seismogenic potential of the High Durance Fault constrained by 20 yr of GNSS measurements in the Western European Alps 2020 Geophysical Journal International
Vol. 222(3), pp. 2136-2146
article DOI
Abstract: Due to the steady moderate seismicity observed along the Briançon
seismic arc, in the south-western French Alps, three temporary
GNSS (Global Navigation Satellite System) surveys took place in
1996, 2006 and 2011, across a \sim50 texttimes
60 kmtexttwosuperior wide area, to investigate the surface
deformation field. The horizontal velocity field computed from
these three surveys showed an east-west extension in the
network. A fourth campaign was led in 2016, creating a 20 yr
observation span, resulting in measurements which reach a
sufficient accuracy to assess whether extension found within the
Briançon network is localized onto any particular tectonic
feature. Several faults in this area are known to be active
normal faults. Assessing the localization of the deformation may
lead to a better understanding of the active tectonics of the
Alpine belt. To address this issue, a robust velocity field was
computed from the combination of the different campaign and
permanent GNSS data. Strain rate tensors were derived for the
first time in this area on a 0.1 texttimes 0.1 deg grid to
assess the distribution of the deformation. The regional
deformation appears localized in the Briançon area and
reaches up to 20 \pm 5 nanostrain yr^-1 in
the centre of the network. The observed velocities were
projected on a profile across the network and compared with
modelled interseismic deformation to characterize the behaviour
of the major active faults known in the study zone. While a two-
fault model provides the best fit to the data, a single fault
model has only marginally higher residuals, with parameters
which are more consistent with the seismotectonics of the
region. The localization of the single modelled fault is
consistent with the location of the High Durance Fault (HDF).
Therefore, we used the known geological location of this
structure as a priori information in a block model to compute a
fault slip rate at the interface between the two blocks. The
velocities on the interface indicate 0.4-0.5 mm yr^-1 of
extension, and therefore strain accumulates along the HDF
throughout the seismic cycle. The geodetically derived fault
slip rate is converted into an equivalent seismic moment release
rate, which is consistent within its uncertainty bounds with the
known historical and instrumental seismicity of the
Briançon area.
BibTeX:
@article{2020GeoJI.222.2136M,
author = {Mathey, M. and Walpersdorf, A. and Sue, C. and Baize, S. and Deprez, A.},
title = {Seismogenic potential of the High Durance Fault constrained by 20 yr of GNSS measurements in the Western European Alps},
journal = {Geophysical Journal International},
year = {2020},
volume = {222},
number = {3},
pages = {2136-2146},
doi = {https://doi.org/10.1093/gji/ggaa292}
}

Shinbori, A., Otsuka, Y., Sori, T., Tsugawa, T. and Nishioka, M. Temporal and Spatial Variations of Total Electron Content Enhancements During a Geomagnetic Storm on 27 and 28 September 2017 2020 Journal of Geophysical Research (Space Physics)
Vol. 125(7), pp. e26873
article DOI
Abstract: Temporal and spatial evolutions of total electron content (TEC) and
electron density in the ionosphere during a geomagnetic storm
that occurred on 27 and 28 September 2017 have been investigated
using global TEC data obtained from many Global Navigation
Satellite System stations together with the ionosonde,
geomagnetic field, Jicamarca incoherent scatter and Super Dual
Auroral Radar Network (SuperDARN) radar data. Our analysis
results show that a clear enhancement of the ratio of the TEC
difference (rTEC) first occurs from noon to afternoon at high
latitudes within 1 hr after a sudden increase and expansion of
the high-latitude convection and prompt penetration of the
electric field to the equator associated with the southward
excursion of the interplanetary magnetic field. Approximately
1-2 hr after the onset of the h_mF_2 increase in the
midlatitude and low-latitude regions associated with the high-
latitude convection enhancement, the rTEC and f_oF_2
values begin to increase and the enhanced rTEC region expands to
low latitudes within 1-2 hr. This signature suggests that the
ionospheric plasmas in the F_2 region move at a higher
altitude due to local electric field drift, where the
recombination rate is smaller, and that the electron density
increases due to additional production at the lower altitude in
the sunlit region. Later, another rTEC enhancement related to
the equatorial ionization anomaly appears in the equatorial
region approximately 1 hr after the prompt penetration of the
electric field to the equator and expands to higher latitudes
within 3-4 hr.
BibTeX:
@article{2020JGRA..12526873S,
author = {Shinbori, Atsuki and Otsuka, Yuichi and Sori, Takuya and Tsugawa, Takuya and Nishioka, Michi},
title = {Temporal and Spatial Variations of Total Electron Content Enhancements During a Geomagnetic Storm on 27 and 28 September 2017},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2020},
volume = {125},
number = {7},
pages = {e26873},
doi = {https://doi.org/10.1029/2019JA026873}
}

Hickey, D.A. and Martinis, C.R. All-Sky Imaging Observations of the Interaction Between the Brightness Wave and ESF Airglow Depletions 2020 Journal of Geophysical Research (Space Physics)
Vol. 125(5), pp. e27232
article DOI
Abstract: The midnight temperature maximum (MTM) and equatorial spread F (ESF) are
common processes in the low-latitude ionosphere and
thermosphere. This work shows the first interaction between the
brightness wave (BW), associated with the MTM, and plasma
depletions, associated with ESF. Observations from the El
Leoncito all-sky imager (ASI) (31.8textdegreeS,
69.3textdegreeW, 19.7textdegreeS magnetic latitude) show
concurrent observations of a plasma depletion and a BW. As the
BW passes through the depletion, the depletion is modified and
becomes an enhancement. Concurrent measurements at the conjugate
location show an airglow depletion, indicating that the
enhancement is an evolution of the depletion and not a separate
feature and that it only occurs in one hemisphere. Previous
model results were able to recreate the evolution of an airglow
depletion into an enhancement when there is a poleward wind
combined with converging zonal winds. We discuss how these wind
conditions are often associated with the MTM/BW and can explain
this observed enhancement.
BibTeX:
@article{2020JGRA..12527232H,
author = {Hickey, Dustin A. and Martinis, Carlos R.},
title = {All-Sky Imaging Observations of the Interaction Between the Brightness Wave and ESF Airglow Depletions},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2020},
volume = {125},
number = {5},
pages = {e27232},
doi = {https://doi.org/10.1029/2019JA027232}
}

Aa, E., Zou, S., Eastes, R., Karan, D.K., Zhang, S.-R., Erickson, P.J. and Coster, A.J. Coordinated Ground-Based and Space-Based Observations of Equatorial Plasma Bubbles 2020 Journal of Geophysical Research (Space Physics)
Vol. 125(1), pp. e27569
article DOI
Abstract: This paper presents coordinated and fortuitous ground-based and
spaceborne observations of equatorial plasma bubbles (EPBs) over
the South American area on 24 October 2018, combining the
following measurements: Global-scale Observations of Limb and
Disk far ultraviolet emission images, Global Navigation
Satellite System total electron content data, Swarm in situ
plasma density observations, ionosonde virtual height and drift
data, and cloud brightness temperature data. The new
observations from the Global-scale Observations of Limb and
Disk/ultraviolet imaging spectrograph taken at geostationary
orbit provide a unique opportunity to image the evolution of
plasma bubbles near the F peak height over a large geographic
area from a fixed longitude location. The combined multi-
instrument measurements provide a more integrated and
comprehensive way to study the morphological structure,
development, and seeding mechanism of EPBs. The main results of
this study are as follows: (1) The bubbles developed a westward
tilted structure with 10-15textdegree inclination relative to
the local geomagnetic field lines, with eastward drift velocity
of 80-120 m/s near the magnetic equator that gradually decreased
with increasing altitude/latitude. (2) Wave-like oscillations in
the bottomside F layer and detrended total electron content were
observed, which are probably due to upward propagating
atmospheric gravity waves. The wavelength based on the medium-
scale traveling ionospheric disturbance signature was consistent
with the interbubble distance of \sim500-800 km.
(3) The atmospheric gravity waves that originated from
tropospheric convective zone are likely to play an important
role in seeding the development of this equatorial EPBs event.
BibTeX:
@article{2020JGRA..12527569A,
author = {Aa, Ercha and Zou, Shasha and Eastes, Richard and Karan, Deepak K. and Zhang, Shun-Rong and Erickson, Philip J. and Coster, Anthea J.},
title = {Coordinated Ground-Based and Space-Based Observations of Equatorial Plasma Bubbles},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2020},
volume = {125},
number = {1},
pages = {e27569},
doi = {https://doi.org/10.1029/2019JA027569}
}

Spicher, A., Deshpande, K., Jin, Y., Oksavik, K., Zettergren, M.D., Clausen, L.B.N., Moen, J.I., Hairston, M.R. and Baddeley, L. On the Production of Ionospheric Irregularities Via Kelvin-Helmholtz Instability Associated with Cusp Flow Channels 2020 Journal of Geophysical Research (Space Physics)
Vol. 125(6), pp. e27734
article DOI
Abstract: We present a multi-instrument multiscale study of a channel of enhanced,
inhomogeneous flow in the cusp ionosphere occurring on November
30, 2014. We provide evidence that strong Global Navigation
Satellite System (GNSS) phase scintillations indices
arise from such events, indicating that they are important in
the context of space weather impacts on technology. We compare
in detail two-dimensional maps of ionospheric density, velocity,
and temperatures obtained by the European Incoherent Scatter
Scientific Association Svalbard Radar with scintillation indices
detected from a network of four GNSS receivers around Svalbard
and examine the different sources of free energy for
irregularity creation. We observe that the strongest phase
scintillations occur on the poleward side of the flow channel in
a region of sheared plasma motion and structured low-energy
particle precipitation. As inhomogeneous plasma flows are
evident in our observations, we perform a quantitative,
nonlinear analysis of the Kelvin-Helmholtz instability (KHI) and
its impact on phase scintillations using numerical simulations
from the first principles-based Geospace Environment Model of
Ion-Neutral Interactions and Satellite-beacon Ionospheric-
scintillation Global Model of the upper Atmosphere. Using
representative values consistent with the radar data, we show
that KHI can efficiently create density structures along with
considerable scintillations and is thus likely to contribute
significantly under similar conditions, which are frequent in
the cusp.
BibTeX:
@article{2020JGRA..12527734S,
author = {Spicher, Andres and Deshpande, Kshitija and Jin, Yaqi and Oksavik, Kjellmar and Zettergren, Matthew D. and Clausen, Lasse B. N. and Moen, Jøran I. and Hairston, Marc R. and Baddeley, Lisa},
title = {On the Production of Ionospheric Irregularities Via Kelvin-Helmholtz Instability Associated with Cusp Flow Channels},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2020},
volume = {125},
number = {6},
pages = {e27734},
doi = {https://doi.org/10.1029/2019JA027734}
}

Goodwin, L.V., Nishimura, Y., Coster, A.J., Zhang, S., Nishitani, N., Ruohoniemi, J.M., Anderson, B.J. and Zhang, Q.H. Dayside Polar Cap Density Enhancements Formed During Substorms 2020 Journal of Geophysical Research (Space Physics)
Vol. 125(10), pp. e28101
article DOI
Abstract: The formation of polar cap density enhancements, such as tongues-of-
ionization (TOIs), are often attributed to enhanced dayside
reconnection and convection due to solar wind changes. However,
ionospheric poleward moving density enhancements can also form
in the absence of changes in the solar wind. This study examines
how TOI and patch events that are not triggered by solar wind
changes relate to magnetospheric processes, specifically
substorms. Based on total electron content and Super Dual
Auroral Radar Network (SuperDARN) observations, we find
substorms that occur at the same time as TOIs are associated
with sudden enhancements in dayside poleward flows during the
substorm expansion phase. Active Magnetosphere and Planetary
Electrodynamics Response Experiment (AMPERE) observations also
show enhanced field-aligned currents (FACs) that extend into the
dayside ionosphere during this period. We suggest that the
global enhancement of FACs and convection during these substorms
are the drivers of these TOIs by enhancing dayside convection
and transporting high-density lower-latitude plasma into the
polar cap. However, we also find that not all substorms are
coincident with polar cap density enhancements. A superposed
epoch study showed that the AL index for TOIs during substorms
is not particularly stronger than substorms without TOIs, but
epoch studies of AMPERE observations do show events with TOIs to
have a higher total FAC on both the dayside and nightside. Our
results show the importance of TOI formation during substorms
when solar wind drivers are absent, and the importance of
considering substorms in the global current system. This work
also shows the need to incorporate substorms into models of
high-latitude global convection and currents.
BibTeX:
@article{2020JGRA..12528101G,
author = {Goodwin, L. V. and Nishimura, Y. and Coster, A. J. and Zhang, S. and Nishitani, N. and Ruohoniemi, J. M. and Anderson, B. J. and Zhang, Q. -H.},
title = {Dayside Polar Cap Density Enhancements Formed During Substorms},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2020},
volume = {125},
number = {10},
pages = {e28101},
doi = {https://doi.org/10.1029/2020JA028101}
}

Dinsmore, R., Mathews, J.D., Coster, A., Robinson, R.M., Sarkhel, S., Erickson, P.J. and Urbina, J. Multi-instrument observations of SCIPS: 1. ISR and GPS TEC results 2021 Journal of Atmospheric and Solar-Terrestrial Physics
Vol. 213, pp. 105515
article DOI
Abstract: An uninterrupted multi-day (6-8 May 2013) ionospheric F-region event
with features indicative of medium-scale traveling ionospheric
disturbances (MSTIDs) was detected with the Millstone Hill (MH)
incoherent scatter radar (ISR). It was later identified, with
the addition of Global Positioning System total electron content
(GPS-TEC) imaging, as a novel ionospheric phenomenon. This
phenomenon is herein termed semi-coherent ionospheric pulsing
structures (SCIPS). The presumptive-MSTIDs in this multi-day
event had a -0.5ex1 h period and were
observed during calm-to-minor geomagnetic conditions using both
the vertical-looking (Zenith) and steerable (Millstone Hill
Steerable Antenna, or MISA) MH ISR systems. To image the MH
MSTID events on a larger horizontal scale than is possible with
ISR systems alone, a dense network of GPS TEC receivers was
leveraged. The ISR-observed event was located in the GPS-TEC
data geographically centered on the MH location with a
-0.5ex100 km resolution (pixel size).
However, keogram analysis of the GPS-TEC data revealed that the
event had coherency across the continental United States. The
same technique additionally exposed similar events occurring
globally throughout the observing period. Our multi-instrument
approach allows us to conclude that the event was comprised of
large-scale and continuously forced, semi-coherent ionospheric
pulsing structures (SCIPS) that masqueraded as MSTIDs when
viewed locally. The GPS-TEC images show that the SCIPS were
stationary in longitude on a global scale, but appeared to
propagate in a southward direction in the Northern Hemisphere.
It was not possible to obtain direct imaging in the southern
hemisphere due to the smaller number of receivers. The SCIPS
appear to originate at high latitudes and, in several instances,
were coherent across over 10,000 km. The apparent high latitude
source location, ubiquity, and large-scale coherence of the
SCIPS suggest unexpected impulsive auroral oval sources
containing enough energy to continually force the observed
MSTID-like structures even during low geomagnetic activity
periods.
BibTeX:
@article{2021JASTP.21305515D,
author = {Dinsmore, Ross and Mathews, J. D. and Coster, Anthea and Robinson, R. M. and Sarkhel, Sumanta and Erickson, Philip J. and Urbina, Julio},
title = {Multi-instrument observations of SCIPS: 1. ISR and GPS TEC results},
journal = {Journal of Atmospheric and Solar-Terrestrial Physics},
year = {2021},
volume = {213},
pages = {105515},
doi = {https://doi.org/10.1016/j.jastp.2020.105515}
}

Cai, X., Burns, A.G., Wang, W., Qian, L., Liu, J., Solomon, S.C., Eastes, R.W., Daniell, R.E., Martinis, C.R., McClintock, W.E. and Batista, I.S. Observation of Postsunset OI 135.6 nm Radiance Enhancement Over South America by the GOLD Mission 2021 Journal of Geophysical Research (Space Physics)
Vol. 126(2), pp. e28108
article DOI
Abstract: The Global scale Observation of Limb and Disk (GOLD) mission, for the
first time, provides synoptic two dimensional (2D) maps of OI
135.6 nm observations. These maps describe the unambiguous and
dynamic evolution of nighttime ionospheric F_2 peak electron
densities (N_mF_2) as the 135.6 nm airglow emission
radiance correlates well with N_mF_2 at night. On
November 19, 2018, the 135.6 nm radiance measured by GOLD,
N_mF_2 measured by a digisonde, and GPS total electron
content (TEC) measurements at Cachoeira Paulista (CP) all showed
a postsunset enhancement, with an increase near 22:30 universal
time. The 135.6 nm radiance map showed that this enhancement was
due to the southward movement of the southern equatorial
ionization anomaly (EIA) crest. Therefore, the GOLD observation
showed the linkage between postsunset enhancement of
N_mF_2 and EIA movement. Furthermore, unlike the
southward movement of the southern crest, the corresponding EIA
northern crest, however, did not show northward motion. This is
the first time that the EIA hemispheric asymmetry, which
included both different densities and movement of two crests in
a short time period (lt2 h), was captured. The cause of this
asymmetric movement of the two crests is not clear and requires
further investigation.
BibTeX:
@article{2021JGRA..12628108C,
author = {Cai, Xuguang and Burns, Alan G. and Wang, Wenbin and Qian, Liying and Liu, Jing and Solomon, Stanley C. and Eastes, Richard W. and Daniell, Robert E. and Martinis, Carlos R. and McClintock, William E. and Batista, Inez S.},
title = {Observation of Postsunset OI 135.6 nm Radiance Enhancement Over South America by the GOLD Mission},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2021},
volume = {126},
number = {2},
pages = {e28108},
doi = {https://doi.org/10.1029/2020JA028108}
}

Goncharenko, L.P., Tamburri, C.A., Tobiska, W.K., Schonfeld, S.J., Chamberlin, P.C., Woods, T.N., Didkovsky, L., Coster, A.J. and Zhang, S.-R. A New Model for Ionospheric Total Electron Content: The Impact of Solar Flux Proxies and Indices 2021 Journal of Geophysical Research (Space Physics)
Vol. 126(2), pp. e28466
article DOI
Abstract: We present a new high resolution empirical model for the ionospheric
total electron content (TEC). TEC data are obtained from the
global navigation satellite system (GNSS) receivers with a
1textdegree texttimes 1textdegree spatial resolution
and 5 min temporal resolution. The linear regression model is
developed at 45textdegreeN, 0textdegreeE for the years
2000-2019 with 30 min temporal resolution, unprecedented for
typical empirical ionospheric models. The model describes
dependency of TEC on solar flux, season, geomagnetic activity,
and local time. Parameters describing solar and geomagnetic
activity are evaluated. In particular, several options for solar
flux input to the model are compared, including the 10.7 cm
solar radio flux (F_10.7), the Mg II core to wing ratio, and
formulations of the solar extreme ultraviolet flux (EUV).
Ultimately, the extreme ultraviolet flux presented by the Flare
Irradiance Spectral Model, integrated from 0.05 to 105.05 nm,
best represents the solar flux input to the model. TEC time
delays to this solar parameter on the order of several days as
well as seasonal modulation of the solar flux terms are
included. The Ap_3 index and its history are used to reflect
the influence of geomagnetic activity. The root mean squared
error of the model (relative to the mean TEC observed in the 30
min window) is 1.9539 TECu. A validation of this model for the
first 3 months of 2020 shows excellent agreement with data. The
new model shows significant improvement over the International
Reference Ionosphere 2016 (IRI 2016) when the two are compared
during 2008 and 2012.
BibTeX:
@article{2021JGRA..12628466G,
author = {Goncharenko, Larisa P. and Tamburri, Cole A. and Tobiska, W. Kent and Schonfeld, Samuel J. and Chamberlin, Phillip C. and Woods, Thomas N. and Didkovsky, Leonid and Coster, Anthea J. and Zhang, Shun-Rong},
title = {A New Model for Ionospheric Total Electron Content: The Impact of Solar Flux Proxies and Indices},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2021},
volume = {126},
number = {2},
pages = {e28466},
doi = {https://doi.org/10.1029/2020JA028466}
}

Maute, A., Richmond, A.D., Lu, G., Knipp, D.J., Shi, Y. and Anderson, B. Magnetosphere Ionosphere Coupling via Prescribed Field Aligned Current Simulated by the TIEGCM 2021 Journal of Geophysical Research (Space Physics)
Vol. 126(1), pp. e28665
article DOI
Abstract: The magnetosphere ionosphere (MI) coupling is crucial in modeling the
thermosphere ionosphere (TI) response to geomagnetic activity.
In general circulation models (GCMs) the MI coupling is
typically realized by specifying the ion convection and auroral
particle precipitation patterns from for example, empirical or
assimilative models. Assimilative models, such as the
Assimilative Mapping of Ionospheric Electrodynamics, have the
advantage that the ion convection and auroral particle
precipitation patterns are mutually consistent and based on
available observations. However, assimilating a large set of
diverse data requires expert knowledge and is time consuming.
Empirical models, on the other hand, are convenient to use, but
do not capture all the observed spatial and temporal variations.
With the availability of Active Magnetosphere and Planetary
Electrodynamics Response Experiment (AMPERE) data, there is an
opportunity for employing field aligned currents (FAC) in GCMs
to represent the MI coupling. In this study, we will introduce a
new method which enables us to use observed FAC in GCMs and
solve for the interhemispherically asymmetric electric potential
distribution. We compare Thermosphere Ionosphere Electrodynamics
General Circulation Model (TIEGCM) simulations of a geomagnetic
storm period using the new approach and two other often used
methods for specifying MI coupling based on empirical and
assimilative high latitude electric potentials. The comparison
shows general similarities of the TI storm time response and
improved temporal variability of the new method compared to
using empirical models, but results also illustrate substantial
differences due to our uncertain knowledge about the MI coupling
process.
BibTeX:
@article{2021JGRA..12628665M,
author = {Maute, A. and Richmond, A. D. and Lu, G. and Knipp, D. J. and Shi, Y. and Anderson, B.},
title = {Magnetosphere Ionosphere Coupling via Prescribed Field Aligned Current Simulated by the TIEGCM},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2021},
volume = {126},
number = {1},
pages = {e28665},
doi = {https://doi.org/10.1029/2020JA028665}
}

Alshawaf, F., Fuhrmann, T., Heck, B., Hinz, S., Knoepfler, A., Luo, X., Mayer, M., Schenk, A., Thiele, A. and Westerhaus, M. Atmospheric Water Vapour Determination by the Integration of InSAR and GNSS Observation 2012
Vol. 2011(January)Lecture Notes in Geoinformation and Cartography, pp. 19-23
incollection DOI URL
BibTeX:
@incollection{Alshawaf2012a,
author = {Alshawaf, Fadwa and Fuhrmann, Thomas and Heck, Bernhard and Hinz, Stefan and Knoepfler, Andreas and Luo, Xiaoguang and Mayer, Michael and Schenk, Andreas and Thiele, Antje and Westerhaus, Malte},
title = {Atmospheric Water Vapour Determination by the Integration of InSAR and GNSS Observation},
booktitle = {Lecture Notes in Geoinformation and Cartography},
publisher = {Springer Science backslashmathplus Business Media},
year = {2012},
volume = {2011},
number = {January},
pages = {19--23},
url = {http://dx.doi.org/10.1007/978-3-642-32714-8_10},
doi = {https://doi.org/10.1007/978-3-642-32714-8%7B%5C_%7D10}
}

Alshawaf, F., Fersch, B., Hinz, S., Kunstmann, H., Mayer, M. and Meyer, F.J. Water vapor mapping by fusing InSAR and GNSS remote sensing data and atmospheric simulations 2015 Hydrology and Earth System Sciences
Vol. 19(12), pp. 4747-4764
article DOI URL
Abstract:

Data fusion aims at integrating multiple data sources that can be redundant or complementary to produce complete, accurate information of the parameter of interest. In this work, data fusion of precipitable water vapor (PWV) estimated from remote sensing observations and data from the Weather Research and Forecasting (WRF) modeling system is applied to provide complete, accurate grids of PWV. Our goal is to infer spatially continuous, precise grids of PWV from heterogeneous data sets. This is done by a geostatistical data fusion approach based on the method of fixed-rank kriging. The first data set contains absolute maps of atmospheric water vapor produced by combining observations from Global Navigation Satellite Systems (GNSS) and Interferometric Synthetic Aperture Radar (InSAR). These PWV maps have a high spatial density and an accuracy of submillimeter; however, data are missing in regions of low coherence (e.g., forests and vegetated areas). The PWV maps simulated by the WRF model represent the second data set. The model maps are available for wide areas, but they have a coarse spatial resolution and a yet limited accuracy. The PWV maps inferred by the data fusion at any spatial resolution are more accurate than those inferred from single data sets. In addition, using the fixed-rank kriging method, the computational burden is significantly lower than that for ordinary kriging.

BibTeX:
@article{Alshawaf2015,
author = {Alshawaf, F. and Fersch, B. and Hinz, S. and Kunstmann, H. and Mayer, M. and Meyer, F. J.},
title = {Water vapor mapping by fusing InSAR and GNSS remote sensing data and atmospheric simulations},
journal = {Hydrology and Earth System Sciences},
publisher = {Copernicus GmbH},
year = {2015},
volume = {19},
number = {12},
pages = {4747--4764},
url = {http://dx.doi.org/10.5194/hessd-12-363-2015 http://www.hydrol-earth-syst-sci-discuss.net/12/363/2015/},
doi = {https://doi.org/10.5194/hess-19-4747-2015}
}

Alshawaf, F., Fuhrmann, T., Knöpfler, A., Luo, X., Mayer, M., Hinz, S. and Heck, B. Accurate Estimation of Atmospheric Water Vapor Using GNSS Observations and Surface Meteorological Data 2015 IEEE Transactions on Geoscience and Remote Sensing
Vol. 53(7), pp. 3764-3771
article DOI URL
BibTeX:
@article{Alshawaf2015b,
author = {Alshawaf, F. and Fuhrmann, T. and Knöpfler, A. and Luo, X. and Mayer, M. and Hinz, S. and Heck, B.},
title = {Accurate Estimation of Atmospheric Water Vapor Using GNSS Observations and Surface Meteorological Data},
journal = {IEEE Transactions on Geoscience and Remote Sensing},
publisher = {Institute of Electrical & Electronics Engineers (IEEE)},
year = {2015},
volume = {53},
number = {7},
pages = {3764--3771},
url = {http://dx.doi.org/10.1109/tgrs.2014.2382713},
doi = {https://doi.org/10.1109/TGRS.2014.2382713}
}

Altamimi, Z., Collilieux, X. and Métivier, L. ITRF2008: An improved solution of the international terrestrial reference frame 2011 Journal of Geodesy
Vol. 85(8), pp. 457-473
article DOI URL
Abstract: ITRF2008 is a refined version of the International Terrestrial Reference Frame based on reprocessed solutions of the four space geodetic techniques: VLBI, SLR, GPS and DORIS, spanning 29, 26, 12.5 and 16 years of observations, respectively. The input data used in its elaboration are time series (weekly from satellite techniques and 24-h session-wise from VLBI) of station positions and daily Earth Orientation Parameters (EOPs). The ITRF2008 origin is defined in such a way that it has zero translations and translation rates with respect to the mean Earth center of mass, averaged by the SLR time series. Its scale is defined by nullifying the scale factor and its rate with respect to the mean of VLBI and SLR long-term solutions as obtained by stacking their respective time series. The scale agreement between these two technique solutions is estimated to be 1.05 ± 0.13 ppb at epoch 2005.0 and 0.049 ± 0.010 ppb/yr. The ITRF2008 orientation (at epoch 2005.0) and its rate are aligned to the ITRF2005 using 179 stations of high geodetic quality. An estimate of the origin components from ITRF2008 to ITRF2005 (both origins are defined by SLR) indicates differences at epoch 2005.0, namely: −0.5, −0.9 and −4.7 mm along X , Y and Z -axis, respectively. The translation rate differences between the two frames are zero for Y and Z , while we observe an X -translation rate of 0.3 mm/yr. The estimated formal errors of these parameters are 0.2 mm and 0.2 mm/yr, respectively. The high level of origin agreement between ITRF2008 and ITRF2005 is an indication of an imprecise ITRF2000 origin that exhibits a Z -translation drift of 1.8 mm/yr with respect to ITRF2005. An evaluation of the ITRF2008 origin accuracy based on the level of its agreement with ITRF2005 is believed to be at the level of 1 cm over the time-span of the SLR observations. Considering the level of scale consistency between VLBI and SLR, the ITRF2008 scale accuracy is evaluated to be at the level of 1.2 ppb (8 mm at the equator) over the common time-span of the observations of both techniques. Although the performance of the ITRF2008 is demonstrated to be higher than ITRF2005, future ITRF improvement resides in improving the consistency between local ties in co-location sites and space geodesy estimates.
BibTeX:
@article{Altamimi2011a,
author = {Altamimi, Zuheir and Collilieux, Xavier and Métivier, Laurent},
title = {ITRF2008: An improved solution of the international terrestrial reference frame},
journal = {Journal of Geodesy},
publisher = {Springer Science backslashmathplus Business Media},
year = {2011},
volume = {85},
number = {8},
pages = {457--473},
url = {http://dx.doi.org/10.1007/s00190-011-0444-4 http://link.springer.com/10.1007/s00190-011-0444-4},
doi = {https://doi.org/10.1007/s00190-011-0444-4}
}

Asensio, E., Khazaradze, G., Echeverria, A., King, R.W. and Vilajosana, I. GPS studies of active deformation in the Pyrenees 2012 Geophysical Journal International
Vol. 190(2), pp. 913-921
article DOI URL
Abstract: The Pyrenees mountain belt, which separates the Iberian Peninsula from the rest of the European continent, is part of the Alpine–Himalayan orogenic belt, formed as a result of a collision between the African and Eurasian Plates. Although the instrumental seismicity in the Pyrenees is moderate, in the past centuries a number of destructive earthquakes have occurred, which could indicate continuing tectonic activity of the area. We analyse GPS observations spanning 3.5 yr from 35 continuous stations in the Pyrenees region and find significant on-going extension perpendicular to the range at 2.5 ± 0.5 nstrain yr–1, with the possibility of higher strain rates concentrated in the westernmost part of the range. This finding is in agreement with the predominantly normal faulting focal mechanisms of earthquakes that occur in the area and suggests a recurrence time for magnitude 6.5 earthquakes of 2200–2500 yr.
BibTeX:
@article{Asensio2012a,
author = {Asensio, E. and Khazaradze, G. and Echeverria, A. and King, R. W. and Vilajosana, I.},
title = {GPS studies of active deformation in the Pyrenees},
journal = {Geophysical Journal International},
publisher = {Oxford University Press (OUP)},
year = {2012},
volume = {190},
number = {2},
pages = {913--921},
url = {http://dx.doi.org/10.1111/j.1365-246x.2012.05525.x},
doi = {https://doi.org/10.1111/j.1365-246X.2012.05525.x}
}

van Baelen, J., Aubagnac, J.-P., Doerflinger, E., Bock, O., Walpersdorf, A. and Masson, F. IHOP: the French GPS-water vapor contribution 2003 EGS - AGU - EUG Joint Assembly  inproceedings
BibTeX:
@inproceedings{Baelen2003a,
author = {van Baelen, J and Aubagnac, J.-P. and Doerflinger, E and Bock, O and Walpersdorf, A and Masson, F},
title = {IHOP: the French GPS-water vapor contribution},
booktitle = {EGS - AGU - EUG Joint Assembly},
year = {2003}
}

Baize, S., Cushing, E.M., Lemeille, F. and Jomard, H. Updated seismotectonic zoning scheme of Metropolitan France, with reference to geologic and seismotectonic data 2013 Bulletin de la Societe Geologique de France
Vol. 184(3), pp. 225-259
article DOI URL
Abstract: This work presents the seismotectonic zoning scheme of Metropolitan France developed by the IRSN (French Institute for Radioprotection and Nuclear Safety) within the framework of its seismic hazard assessment activities. It is the outcome of many years of work following the publication of the “seismotectonic atlas” in 1993 [Grellet et al., 1993].This scheme supports the assessment of seismic hazard by IRSN. It takes into account the most recent data concerning the deep and surface geology, as well as those related to seismotectonics and tectonic activity. It finally includes 67 surface seismotectonic zones (STZ), as well as a catalogue of 74 faults or structures (named hereafter “potential active faults”) for which indications of Neogene to Quaternary displacement can be inferred. The description of the zoning scheme comes along with an estimation of the uncertainty on the boundary location between adjacent STZ. We also qualitatively determine a “relevance order” for each limit, so as to illustrate their reliability to separate regions of different seismogenic potential. Also, we attributed to the faults an indication whose purpose is to reflect the recent character of their activity, and thus their seismotectonic potential.This assessment of uncertainties was undertaken to better integrate the zoning scheme in the general approach, which arises from recent studies, namely the propagation of the uncertainties in seismic hazard evaluation, whether deterministic or probabilistic.
BibTeX:
@article{Baize2013a,
author = {Baize, Stéphane and Cushing, Edward Marc and Lemeille, Francis and Jomard, Hervé},
title = {Updated seismotectonic zoning scheme of Metropolitan France, with reference to geologic and seismotectonic data},
journal = {Bulletin de la Societe Geologique de France},
publisher = {GeoScienceWorld},
year = {2013},
volume = {184},
number = {3},
pages = {225--259},
url = {http://bsgf.geoscienceworld.org/content/184/3/225.abstract},
doi = {https://doi.org/10.2113/gssgfbull.184.3.225}
}

Barani, S., Scafidi, D. and Eva, C. Strain rates in northwestern Italy from spatially smoothed seismicity 2010 Journal of Geophysical Research: Solid Earth
Vol. 115(B7), pp. 1-16
article DOI URL
Abstract: This work presents seismic strain rate maps for the Western Alps and Northern Apennines (northern Italy) as derived from an earthquake catalog collecting both historical and instrumental data. Strain rates are calculated on the basis of the rate of seismic moment release using the Anderson method. Unlike previous applications, which determined the total strain rate associated with specific seismogenic sources, we have employed an innovative zoneless approach based on a spatially smoothed seismicity method. In addition, a Monte Carlo simulation procedure is applied to allow for uncertainty in the input data (e.g., magnitude to moment conversion, seismogenic thickness, maximum earthquake magnitude). Strain rate maps are developed by summing the moments of the earthquakes reported in the catalog and by using two different earthquake recurrence relations. Our results indicate that deformation rates are quite high, ranging from about 2 to 12 × 10&#8722;9 yr&#8722;1 in the Northern Apennines and from 0.5 to 6 × 10&#8722;9 yr&#8722;1 in the Western Alps. These values, however, are &#8764;1 order less than those derived from Global Positioning System measurements, suggesting that a portion of the recent deformation in northwestern Italy is related to aseismic processes. The discrepancies between seismic and geodetic strain rates may also indicate that the record of seismicity may not provide a sufficient time window for assessment of secular rates of moment release (or secular deformation rates) and rates of recurrence of large magnitude earthquakes in the study area.
BibTeX:
@article{Barani2010a,
author = {Barani, Simone and Scafidi, Davide and Eva, Claudio},
title = {Strain rates in northwestern Italy from spatially smoothed seismicity},
journal = {Journal of Geophysical Research: Solid Earth},
publisher = {Wiley-Blackwell},
year = {2010},
volume = {115},
number = {B7},
pages = {1--16},
url = {http://dx.doi.org/10.1029/2009jb006637},
doi = {https://doi.org/10.1029/2009JB006637}
}

Barba, S., Carafa, M.M., Mariucci, M.T., Montone, P. and Pierdominici, S. Present-day stress-field modelling of southern Italy constrained by stress and GPS data 2010 Tectonophysics
Vol. 482(1-4), pp. 193-204
article DOI URL
Abstract: The present-day tectonic setting of the Italian peninsula is very complex and involves competing geodynamic processes. In this context, southern peninsular Italy is characterised by extension along the Apenninic belt and in the Tyrrhenian margin and by transpression in the Apulia-Gargano region. The extension is well defined by means of geological, seismological, and contemporary stress data. For the latter only few data are available in the Apulia-Gargano region, leaving the state of stress in that area unresolved. Here we develop a finite-element model of the southern Italian region in order to predict the contemporary stress field. Our model predictions are constrained by model-independent observations of the orientation of maximum horizontal stress (SHmax), the tectonic regime, and the horizontal velocities derived from GPS observations. We performed a blind test with 31 newly acquired SHmax orientations in the Southern Apennines. These new data come from the analysis of orehole breakouts performed in 46 deep oil exploration wells ranging in depth from 1300 to 5500 m. The model results agree with the stress data that define a prevailing NW-SE SHmax orientation along the Apenninic belt and foredeep and thus are capable to predict the stress field where no stress information is available. We first analyse how much model predictions, based on older data, deviate from present-day stress data and then recalibrate the models based on our new stress data, giving insight into the resolution of both models and data. In the studied region, which is affected by low deformation rates, we find that geodetic data alone cannot resolve such low levels of deformation due to the high relative measurement errors. We conclude that both GPS and stress data are required to constrain model results. © 2009 Elsevier B.V. All rights reserved.
BibTeX:
@article{Barba2010a,
author = {Barba, Salvatore and Carafa, Michele M.C. and Mariucci, Maria Teresa and Montone, Paola and Pierdominici, Simona},
title = {Present-day stress-field modelling of southern Italy constrained by stress and GPS data},
journal = {Tectonophysics},
publisher = {Elsevier BV},
year = {2010},
volume = {482},
number = {1-4},
pages = {193--204},
url = {http://dx.doi.org/10.1016/j.tecto.2009.10.017},
doi = {https://doi.org/10.1016/j.tecto.2009.10.017}
}

Bennitt, G.V. and Jupp, A. Operational Assimilation of GPS Zenith Total Delay Observations into the Met Office Numerical Weather Prediction Models 2012 Monthly Weather Review
Vol. 140(8), pp. 2706-2719
article DOI URL
BibTeX:
@article{Bennitt2012a,
author = {Bennitt, Gemma V. and Jupp, Adrian},
title = {Operational Assimilation of GPS Zenith Total Delay Observations into the Met Office Numerical Weather Prediction Models},
journal = {Monthly Weather Review},
publisher = {American Meteorological Society},
year = {2012},
volume = {140},
number = {8},
pages = {2706--2719},
url = {http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-11-00156.1},
doi = {https://doi.org/10.1175/MWR-D-11-00156.1}
}

Bock, O., Doerflinger, E., Masson, F., Walpersdorf, A., Van-Baelen, J., Tarniewicz, J., Troller, M., Somieski, A., Geiger, A. and Bürki, B. GPS water vapor project associated to the ESCOMPTE programme: Description and first results of the field experiment 2004 Physics and Chemistry of the Earth
Vol. 29(2-3), pp. 149-157
article DOI
Abstract: A dense network of 17 dual frequency GPS receivers has been operated for two weeks during June 2001 within a 20 km × 20 km area around Marseille, France, as part of the ESCOMPTE field campaign ([Cros et al., 2004. The ESCOMPTE program: an overview. Atmos. Res. 69, 241-279]; http://medias.obs-mip.fr/escompte). The goal of this GPS experiment was to provide GPS data allowing for tomographic inversions and their validation within a well-documented observing period (the ESCOMPTE campaign). Simultaneous water vapor radiometer, solar spectrometer, Raman lidar and radiosonde data are used for comparison and validation. In this paper, we highlight the motivation, issues and describe the GPS field experiment. Some first results of integrated water vapor retrievals from GPS and the other sensing techniques are presented. The strategies for GPS data processing and tomographic inversions are discussed. © 2004 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Bock2004a,
author = {Bock, O. and Doerflinger, E. and Masson, F. and Walpersdorf, A. and Van-Baelen, J. and Tarniewicz, J. and Troller, M. and Somieski, A. and Geiger, A. and Bürki, B.},
title = {GPS water vapor project associated to the ESCOMPTE programme: Description and first results of the field experiment},
journal = {Physics and Chemistry of the Earth},
year = {2004},
volume = {29},
number = {2-3},
pages = {149--157},
doi = {https://doi.org/10.1016/j.pce.2004.01.014}
}

Bock, O., Bosser, P., Pacione, R., Nuret, M., FourriÃ©, N. and Parracho, A. A high-quality reprocessed ground-based GPS dataset for atmospheric process studies, radiosonde and model evaluation, and reanalysis of HyMeX Special Observing Period 2016 Quarterly Journal of the Royal Meteorological Society
Vol. 142, pp. 56-71
article DOI URL
Abstract: In the framework of the Hydrological cycle in the Mediterranean Experiment (HyMeX) project, measurements from more than 1000 ground-based Global Positioning System (GPS) receivers located in the northwestern Mediterranean area are reprocessed using a single piece of GPS software for the period from 1 September 2012 to 31 March 2013. A special screening procedure is developed for the removal of outliers in the GPS Zenith Total Delay (ZTD) data. ZTD data are converted to integrated water vapour (IWV) using surface pressure information from an AROME-WMED operational analysis. The reprocessed ZTD and IWV data are used to assess the accuracy of the near-real time E-GVAP ZTD data assimilated in operational numerical weather prediction systems and to validate the IWV data from the AROME-WMED operational analysis and AROME-WMED reanalysis 1, and from radiosonde observations. The mean differences between E-GVAP and reprocessed ZTD data are not negligible and lie in the range from -3 to +3 mm. The standard deviations of differences are between 4 and 8 mm. The comparisons of IWV from AROME-WMED analyses and the reprocessed GPS data show high quality of the analyses where operational GPS data are assimilated and lower quality where no GPS data are assimilated. Small but significant biases are found in the radiosonde data during daytime (-0.5 to +1.4 kg m(-2)), but their origin is not determined so far. Thanks to the high spatial density of the reprocessed GPS stations, both the large-scale and small-scale variations in IWV can be documented. The case of HyMeX Intensive Observing Period 8 is presented as an example of a heavy precipitation event. This work suggests that improved quality of the humidity fields can be expected of the future AROME-WMED reanalysis 2 as a result of the assimilation of the reprocessed GPS data.
BibTeX:
@article{Bock2016a,
author = {Bock, O. and Bosser, P. and Pacione, R. and Nuret, M. and FourriÃ©, N. and Parracho, A.},
title = {A high-quality reprocessed ground-based GPS dataset for atmospheric process studies, radiosonde and model evaluation, and reanalysis of HyMeX Special Observing Period},
journal = {Quarterly Journal of the Royal Meteorological Society},
publisher = {Wiley-Blackwell},
year = {2016},
volume = {142},
pages = {56--71},
url = {http://dx.doi.org/10.1002/qj.2701},
doi = {https://doi.org/10.1002/qj.2701}
}

Boniface, K., Champollion, C., Masson, F. and Ducrocq, V. Characterisation of Mediterranean heavy rainfall events from GPS water vapour monitoring 2010
Vol. 12EGU General Assembly Conference Abstracts, pp. 11626
inproceedings
BibTeX:
@inproceedings{Boniface2010a,
author = {Boniface, Karen and Champollion, Cédric and Masson, Frédéric and Ducrocq, Véronique},
title = {Characterisation of Mediterranean heavy rainfall events from GPS water vapour monitoring},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2010},
volume = {12},
pages = {11626}
}

Boniface, K., Champollion, C., Chery, J., Ducrocq, V., Rocken, C., Doerflinger, E. and Collard, P. Potential of shipborne GPS atmospheric delay data for prediction of Mediterranean intense weather events 2012 Atmospheric Science Letters
Vol. 13(4), pp. 250-256
article DOI URL
BibTeX:
@article{Boniface2012a,
author = {Boniface, K. and Champollion, C. and Chery, J. and Ducrocq, V. and Rocken, C. and Doerflinger, E. and Collard, P.},
title = {Potential of shipborne GPS atmospheric delay data for prediction of Mediterranean intense weather events},
journal = {Atmospheric Science Letters},
publisher = {Wiley-Blackwell},
year = {2012},
volume = {13},
number = {4},
pages = {250--256},
url = {http://dx.doi.org/10.1002/asl.391},
doi = {https://doi.org/10.1002/asl.391}
}

Boniface, K., Walpersdorf, A., Guyomarc'H, G., Deliot, Y., Karbou, F., Vionnet, V. and Nievinski, F. GNSS reflectometry measurement of snow depth and soil moisture in the French Alps 2015
Vol. 2015-NovemberInternational Geoscience and Remote Sensing Symposium (IGARSS), pp. 5205-5207
inproceedings DOI URL
Abstract: © 2015 IEEE.Over the last ten years Earth observing systems have grown considerably and thus allow the use of Global Navigation Satellite System (GNSS) signals for remote sensing. Several studies in the U.S. have proven the ability of existing GNSS ground networks to measure environmental parameters quantifying essential surface conditions for the understanding of the water cycle. This is possible by taking advantage of reflected signals around geodetic stations. Improved characterization of environmental disturbances in GNSS signals is also essential to increase the accuracy of future GNSS measurement for applications in Earth Sciences. GNSS reflectometry provides these surface parameters at an intermediate scale that can bridge the lack of data between in situ and satellite observations. Here we adapt and develop for the first time the GNSS reflectometry method using the existing sites of the French national GNSS permanent network (RENAG) for snow and soil moisture applications.
BibTeX:
@inproceedings{Boniface2015a,
author = {Boniface, K. and Walpersdorf, A. and Guyomarc'H, G. and Deliot, Y. and Karbou, F. and Vionnet, V. and Nievinski, F.},
title = {GNSS reflectometry measurement of snow depth and soil moisture in the French Alps},
booktitle = {International Geoscience and Remote Sensing Symposium (IGARSS)},
publisher = {Institute of Electrical & Electronics Engineers (IEEE)},
year = {2015},
volume = {2015-November},
pages = {5205--5207},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=7327007},
}

Bosy, J., Kontny, B. and Borkowski, A. IGS/EPN reference frame realization in local GPS networks 2009
Vol. 134International Association of Geodesy Symposia, pp. 197-203
incollection DOI URL
Abstract: The modern geodetic reference systems (e. g. ITRS) are realized bybackslashnreference frames, i.e. a set of stations with position coordinates at abackslashnreference epoch and station velocities (e. g. ITRF2000). IGSbackslashn(International GNSS Service) global network and EPN (EUREF PermanentbackslashnNetwork) regional network stations are parametrized in this way. Thebackslashnmain IGS/EPN products (gained daily and weekly) are estimated stationbackslashncoordinates and velocities, as well as orbits' and ionospheric andbackslashntropospheric parameters. The connection of local GPS networks withbackslashnIGS/EPN stations enables to use the above products. In this publicationbackslashnthe method of EPN/IGS reference stations selection for the purpose ofbackslashnlocal GPS networks is presented. Two approaches are applied: stationbackslashnvelocity analysis and cluster analysis. It has also been suggested tobackslashnprocess permanent and epoch observations in local GPS networks, whichbackslashnare based on IGS global networks and EPN regional networks' solutionsbackslashnjointly.
BibTeX:
@incollection{Bosy2009a,
author = {Bosy, J. and Kontny, B. and Borkowski, A.},
title = {IGS/EPN reference frame realization in local GPS networks},
booktitle = {International Association of Geodesy Symposia},
publisher = {Springer Science backslashmathplus Business Media},
year = {2009},
volume = {134},
pages = {197--203},
url = {http://dx.doi.org/10.1007/978-3-642-00860-3_31},
doi = {https://doi.org/10.1007/978-3-642-00860-3%7B%5C_%7D31}
}

Boudevillain, B., Argence, S., Claud, C., Ducrocq, V., Joly, B., Joly, A., Lambert, D., Nuissier, O., Plu, M., Ricard, D., Arbogast, P., Berne, A., Chaboureau, J.-P., Chapon, B., Crepin, F., Delrieu, G., Doerflinger, E., Funatsu, B., Kirstetter, P.-E., Masson, F., Maynard, K., Richard, E., Sanchez, E., Terray, L. and Walpersdorf, A. Projet Cyprim, partie I: Cyclogenèses et précipitations intenses en région méditerranéenne: origines et caractéristiques 2009 La Météorologie
Vol. 66(66), pp. 18-28
article DOI URL
Abstract: Le premier volet du projet Cyprim vise à mieux identifier les précurseurs des cyclogenèses et des précipitations intenses en région méditerranéenne. Cet article en présente les principaux résultats. Il est question des ingrédients météorologiques à l'origine de ces systèmes, de la grande à la mésoéchelle, des causes des fortes intensités, localisations et parfois stationnarité des récipitations associées. Le coeur de l'article présente des méthodes d'identification des anomalies de tourbillon potentiel liées à l'occurrence d'événements précipitants intenses et dresse une climatologie de ces anomalies. Les perspectives d'exploitation de cette information pour améliorer la qualité des prévisions sont évoquées. The first part of the CYPRIM project (Cyclogenesis and intense precipitations in the Mediterranean region) aims at a better identification of the precursor structures of cyclogenesis and heavy precipitation in the Mediterranean region. This article presents the main results. It mentions the meteorological ingredients from which these systems originate from the large to themesoscale, the reasons for large intensities, the localization and sometimes stationarity of the associated precipitations. The heart of the article shows methods for identifiying potential vorticity anomalies involved in the occurrence of heavy precipitation events and sets up a climatology of these anomalies.The perspectives of the usefulness of this information for improving forecast quality are discussed.
BibTeX:
@article{Boudevillain2009a,
author = {Boudevillain, Brice and Argence, Sébastien and Claud, Chantal and Ducrocq, Véronique and Joly, Bruno and Joly, Alain and Lambert, Dominique and Nuissier, Olivier and Plu, Matthieu and Ricard, Didier and Arbogast, Philippe and Berne, Alexis and Chaboureau, Jean-Pierre and Chapon, Beno\it and Crepin, Fabien and Delrieu, Guy and Doerflinger, Erik and Funatsu, Beatriz and Kirstetter, Pierre-Emmanuel and Masson, Frederic and Maynard, Karine and Richard, Evelyne and Sanchez, Emilia and Terray, Laurent and Walpersdorf, Andrea},
title = {Projet Cyprim, partie I: Cyclogenèses et précipitations intenses en région méditerranéenne: origines et caractéristiques},
journal = {La Météorologie},
publisher = {INIST-CNRS},
year = {2009},
volume = {66},
number = {66},
pages = {18--28},
url = {http://documents.irevues.inist.fr/handle/2042/28828},
doi = {https://doi.org/10.4267/2042/28828}
}

Bouin, M.N. and Wöppelmann, G. Land motion estimates from GPS at tide gauges: A geophysical evaluation 2010 Geophysical Journal International
Vol. 180(1), pp. 193-209
article DOI URL
Abstract: Space geodesy applications have mainly been limited to horizontal deformations due to a number of restrictions on the vertical component accuracy. Monitoring vertical land motion is nonetheless of crucial interest in observations of long-term sea level change or postglacial rebound measurements. Here, we present a global vertical velocity field obtained with more than 200 permanent GPS stations, most of them colocated with tide gauges (TGs). We used a state of the art, homogeneous processing strategy to ensure that the reference frame was stable throughout the observation period of almost 10 yr. We associate realistic uncertainties to our vertical rates, taking into account the time-correlation noise in the time-series. The results are compared with two independent geophysical vertical velocity fields: (1) vertical velocity estimates using long-term TG records and (2) postglacial model predictions from the ICE-5G (VM2) adjustment. The quantitative agreement of the GPS vertical velocities with the ‘internal estimates’ of vertical displacements using the TG record is very good, with a mean difference of −0.13 ± 1.64 mm yr−1 on more than 100 sites. For 84 per cent of the GPS stations considered, the vertical velocity is confirmed by the TG estimate to within 2 mm yr−1. The overall agreement with the glacial isostatic adjustment (GIA) model is good, with discrepancy patterns related either to a local misfit of the model or to active tectonics. For 72 per cent of the sites considered, the predictions of the GIA model agree with the GPS results to within two standard deviations. Most of the GPS velocities showing discrepancies with respect to the predictions of the GIA model are, however, consistent with previously published space geodesy results. We, in turn, confirm the value of 1.8 ± 0.5 mm yr−1 for the 20th century average global sea level rise, and conclude that GPS is now a robust tool for vertical land motion monitoring which is accurate at least at 1 mm yr−1.
BibTeX:
@article{Bouin2010a,
author = {Bouin, M. N. and Wöppelmann, G.},
title = {Land motion estimates from GPS at tide gauges: A geophysical evaluation},
journal = {Geophysical Journal International},
publisher = {Oxford University Press (OUP)},
year = {2010},
volume = {180},
number = {1},
pages = {193--209},
url = {http://dx.doi.org/10.1111/j.1365-246x.2009.04411.x},
doi = {https://doi.org/10.1111/j.1365-246X.2009.04411.x}
}

Brenot, H., Ducrocq, V., Walpersdorf, A., Champollion, C. and Caumont, O. GPS zenith delay sensitivity evaluated from high-resolution numerical weather prediction simulations of the 8-9 September 2002 flash flood over southeastern France 2006 Journal of Geophysical Research Atmospheres
Vol. 111(15), pp. D15105
article DOI
Abstract: Estimations of zenith total delays (ZTD) were obtained during postprocessingbackslashnof a high-resolution (2.4 km) nonhydrostatic atmospheric model (Méso-NH).backslashnThese estimations were used to determine their sensitivity with respectbackslashnto formulations of atmospheric refractivity, the approximation ofbackslashnzenith hydrostatic delays (ZHD) deduced from ground pressure, andbackslashnthe contributions of hydrometeors. The factor κ for the conversionbackslashnof zenith wet delay (ZWD) to integrated water vapor (IWV) was examined.backslashnMéso-NH is applied here to the extreme flash flood event of 8–9 Septemberbackslashn2002 in southeastern France. The use of the hydrostatic formulationbackslashn(to infer ZHD) leads to an overestimation of up to 18 mm with respectbackslashnto the vertical integration of refractivity. Delay contributionsbackslashnof hydrometeors simulated by the high-resolution model reached morebackslashnthan 70 mm (≈11 kg/m2 IWV) in the heart of the convective cells inbackslashnthe case of the extreme flood event. The mean variations of IWV duebackslashnto the use of different conversion factors (κ used to transform ZWDbackslashnto IWV) are evaluated to be less than 0.3 kg/m2. This is less thanbackslashnthe mean underestimation of IWV by 0.6 kg/m2 relative to the GPS-likebackslashnevaluation of IWV using the hydrostatic formulation and the groundbackslashntemperature. In this study we also use GPS ZTD observations to validatebackslashnthree different numerical simulations of this extreme flood event.backslashnThe simulation with the best fit to the GPS observations is alsobackslashnin best agreement with the surface rainfall measurements.
BibTeX:
@article{Brenot2006a,
author = {Brenot, Hugues and Ducrocq, Véronique and Walpersdorf, Andrea and Champollion, Cédric and Caumont, Olivier},
title = {GPS zenith delay sensitivity evaluated from high-resolution numerical weather prediction simulations of the 8-9 September 2002 flash flood over southeastern France},
journal = {Journal of Geophysical Research Atmospheres},
year = {2006},
volume = {111},
number = {15},
pages = {D15105},
doi = {https://doi.org/10.1029/2004JD005726}
}

Bruyninx, C., Altamimi, Z., Becker, M., Craymer, M., Combrinck, L., Combrink, A., Dawson, J., Dietrich, R., Fernandes, R., Govind, R., Herring, T., Kenyeres, A., King, R., Kreemer, C., Lavallée, D., Legrand, J., Sánchez, L., Sella, G., Shen, Z., Santamar\ia-Gómez, A. and Wöppelmann, G. A Dense Global Velocity Field Based on GNSS Observations: Preliminary Results 2012
Vol. 136International Association of Geodesy Symposia, pp. 19-26
incollection DOI URL
Abstract: In a collaborative effort with the regional sub-commissions within IAG sub-commission 1.3 "Regional Reference Frames", the IAG Working Group (WG) on "Regional Dense Velocity Fields" (see http://epncb.oma.be/IAG) has made a first attempt to create a dense global velocity field. GNSS-based velocity solutions for more than 6,000 continuous and episodic GNSS tracking stations, were proposed to the WG in reply to the first call for participation issued in November 2008. The combination of a part of these solutions was done in a two-step approach: first at the regional level, and secondly at the global level. Comparisons between different velocity solutions show an RMS agreement between 0.3 and 0.5 mm/year resp. for the horizontal and vertical velocities. In some cases, significant disagreements between the velocities of some of the networks are seen, but these are primarily caused by the inconsistent handling of discontinuity epochs and solution numbers. In the future, the WG will re-visit the procedures in order to develop a combination process that is efficient, automated, transparent, and not more complex than it needs to be. © Springer-Verlag Berlin Heidelberg 2012.
BibTeX:
@incollection{Bruyninx2012a,
author = {Bruyninx, C. and Altamimi, Z. and Becker, M. and Craymer, M. and Combrinck, L. and Combrink, A. and Dawson, J. and Dietrich, R. and Fernandes, R. and Govind, R. and Herring, T. and Kenyeres, A. and King, R. and Kreemer, C. and Lavallée, D. and Legrand, J. and Sánchez, L. and Sella, G. and Shen, Z. and Santamar\ia-Gómez, A. and Wöppelmann, G.},
title = {A Dense Global Velocity Field Based on GNSS Observations: Preliminary Results},
booktitle = {International Association of Geodesy Symposia},
publisher = {Springer Science backslashmathplus Business Media},
year = {2012},
volume = {136},
pages = {19--26},
url = {http://dx.doi.org/10.1007/978-3-642-20338-1_3},
doi = {https://doi.org/10.1007/978-3-642-20338-1%7B%5C_%7D3}
}

Calais, E., Nocquet, J.M., Jouanne, F. and Tardy, M. Current strain regime in the Western Alps from continuous Global Positioning System measurements, 1996-2001 2002 Geology
Vol. 30(7), pp. 651-654
article DOI URL
Abstract: Four to six years of continuous measurements at 10 permanent Global Positioning System sites in the Western Alps show horizontal residual velocities of <2 mm/yr with respect to stable Europe; uncertainties range from 0.3 to 1.4 mm/yr. These velocities and the associated strain-rate field indicate that the central part of the range is currently dominated by east-west extension, whereas the southern part shows north-south to northwest-southeast compression. The geodetic and seismotectonic data are consistent with a model where strain is essentially controlled by the counterclockwise rotation of the Adriatic microplate with respect to Eurasia. This rotation, together with the arcuate shape of the contact between the Adriatic microplate and the Alps, induces dextral shear kinematic boundary conditions across the Western Alps, with an additional divergence component in their central part and in Switzerland, and a convergence component in their southern part.
BibTeX:
@article{Calais2002a,
author = {Calais, E. and Nocquet, J. M. and Jouanne, F. and Tardy, M.},
title = {Current strain regime in the Western Alps from continuous Global Positioning System measurements, 1996-2001},
journal = {Geology},
publisher = {Geological Society of America},
year = {2002},
volume = {30},
number = {7},
pages = {651--654},
url = {http://dx.doi.org/10.1130/0091-7613(2002)030<0651:csritw>2.0.co;2},
doi = {https://doi.org/10.1130/0091-7613(2002)030%3C0651:CSRITW%3E2.0.CO;2}
}

Caporali, A., Aichhorn, C., Barlik, M., Becker, M., Fejes, I., Gerhatova, L., Ghitau, D., Grenerczy, G., Hefty, J., Krauss, S., Medak, D., Milev, G., Mojzes, M., Mulic, M., Nardo, A., Pesec, P., Rus, T., Simek, J., Sledzinski, J., Solaric, M., Stangl, G., Stopar, B., Vespe, F. and Virag, G. Surface kinematics in the Alpine-Carpathian-Dinaric and Balkan region inferred from a new multi-network GPS combination solution 2009 Tectonophysics
Vol. 474(1-2), pp. 295-321
article DOI URL
BibTeX:
@article{Caporali2009a,
author = {Caporali, A. and Aichhorn, C. and Barlik, M. and Becker, M. and Fejes, I. and Gerhatova, L. and Ghitau, D. and Grenerczy, G. and Hefty, J. and Krauss, S. and Medak, D. and Milev, G. and Mojzes, M. and Mulic, M. and Nardo, A. and Pesec, P. and Rus, T. and Simek, J. and Sledzinski, J. and Solaric, M. and Stangl, G. and Stopar, B. and Vespe, F. and Virag, G.},
title = {Surface kinematics in the Alpine-Carpathian-Dinaric and Balkan region inferred from a new multi-network GPS combination solution},
journal = {Tectonophysics},
publisher = {Elsevier BV},
year = {2009},
volume = {474},
number = {1-2},
pages = {295--321},
url = {http://dx.doi.org/10.1016/j.tecto.2009.04.035},
doi = {https://doi.org/10.1016/j.tecto.2009.04.035}
}

Cenni, N., Viti, M., Baldi, P., Mantovani, E., Bacchetti, M. and Vannucchi, A. Present vertical movements in Central and Northern Italy from GPS data: Possible role of natural and anthropogenic causes 2013 Journal of Geodynamics
Vol. 71, pp. 74-85
article DOI URL
Abstract: Insights into the present vertical kinematic pattern in Central and Northern Italy are gained by the analysis of GPS data acquired by a network of 262 permanent stations, working over various time intervals since 2001. Uplift is observed in the Alps (up to 5. mm/yr) and Apennines (1-2. mm/yr), whereas subsidence is recognized in the southern Venetian Plain (2-4. mm/yr) and the eastern Po Valley, where the highest rates are observed (up to 9. mm/yr between Reggio Emilia and Rimini). On the other hand, the western part of the Po Valley presents very low vertical rates. The boundary between subsiding and not subsiding Po Valley nearly corresponds to the Giudicarie tectonic discontinuity. It is argued that the different kinematic patterns of the eastern and western Padanian sectors may also be related to the underthrusting of the eastern domain beneath the western one. Some considerations are then reported on how the various causes of vertical movements (tectonic and sedimentological processes) may contribute to the observed kinematics. ?? 2013 Elsevier Ltd.
BibTeX:
@article{Cenni2013a,
author = {Cenni, N. and Viti, M. and Baldi, P. and Mantovani, E. and Bacchetti, M. and Vannucchi, A.},
title = {Present vertical movements in Central and Northern Italy from GPS data: Possible role of natural and anthropogenic causes},
journal = {Journal of Geodynamics},
publisher = {Elsevier BV},
year = {2013},
volume = {71},
pages = {74--85},
url = {http://dx.doi.org/10.1016/j.jog.2013.07.004},
doi = {https://doi.org/10.1016/j.jog.2013.07.004}
}

Champagnac, J.D., Schlunegger, F., Norton, K., von Blanckenburg, F., Abbühl, L.M. and Schwab, M. Erosion-driven uplift of the modern Central Alps 2009 Tectonophysics
Vol. 474(1-2), pp. 236-249
article DOI URL
Abstract: We present a compilation of data of modern tectono-geomorphic processes in the Central European Alps which suggest that observed rock uplift is a response to climate-driven denudation. This interpretation is predominantly based on the recent quantification of basin-averaged Late Holocene denudation rates that are so similar to the pattern and rates of rock uplift rates as determined by geodetic leveling. Furthermore, a GPS data-based synthesis of Adriatic microplate kinematics suggests that the Central Alps are currently not in a state of active convergence. Finally, we illustrate that the Central Alps have acted as a closed system for Holocene redistribution of sediment in which the peri-Alpine lakes have operated as a sink for the erosional products of the inner Central Alps. While various hypotheses have been put forward to explain Central Alpine rock uplift (e.g. lithospheric forcing by convergence, mantle processes, or ice melting) we show with an elastic model of lithospheric deformation, that the correlation between erosion and rock uplift rates reflects a positive feedback between denudation and the associated isostatic response to unloading. Thus, erosion does not passively respond to advection of crustal material as might be the case in actively converging orogens. Rather, we suggest that the geomorphic response of the Alpine topography to glacial and fluvial erosion and the resulting disequilibrium for modern channelized and associated hillslope processes explains much of the pattern of modern denudation and hence rock uplift. Therefore, in a non-convergent orogen such as the Central European Alps, the observed vertical rock uplift is primarily a consequence of passive unloading due to erosion. © 2009 Elsevier B.V. All rights reserved.
BibTeX:
@article{Champagnac2009a,
author = {Champagnac, Jean Daniel and Schlunegger, Fritz and Norton, Kevin and von Blanckenburg, Friedhelm and Abbühl, Luca M. and Schwab, Marco},
title = {Erosion-driven uplift of the modern Central Alps},
journal = {Tectonophysics},
publisher = {Elsevier BV},
year = {2009},
volume = {474},
number = {1-2},
pages = {236--249},
url = {http://dx.doi.org/10.1016/j.tecto.2009.02.024},
doi = {https://doi.org/10.1016/j.tecto.2009.02.024}
}

Champollion, C., Masson, F., Doerflinger, E., van Baelen, J., Anquetin, S., Walpersdorf, A., Chéry, J. and Bock, O. GPS observation of the September 9th 2002 Torrential rainfall in southern France (Gard-Cévennes). 2003 (1)EGS - AGU - EUG Joint Assembly, pp. 2002  inproceedings
BibTeX:
@inproceedings{Champollion2003,
author = {Champollion, C and Masson, F and Doerflinger, E and van Baelen, J and Anquetin, S and Walpersdorf, A and Chéry, J and Bock, O},
title = {GPS observation of the September 9th 2002 Torrential rainfall in southern France (Gard-Cévennes).},
booktitle = {EGS - AGU - EUG Joint Assembly},
year = {2003},
number = {1},
pages = {2002}
}

Champollion, C., Masson, F., Bock, O., Bouin, M., Walpersdorf, A., Doerflinger, E., van Baelen, J. and Brenot, H. GPS Water Vapor Tomography Based on Accurate Estimations of the GPS Tropospheric Parameters 2003 AGU Fall Meeting Abstracts  article
BibTeX:
@article{Champollion2003b,
author = {Champollion, C and Masson, F and Bock, O and Bouin, M and Walpersdorf, A and Doerflinger, E and van Baelen, J and Brenot, H},
title = {GPS Water Vapor Tomography Based on Accurate Estimations of the GPS Tropospheric Parameters},
journal = {AGU Fall Meeting Abstracts},
year = {2003}
}

Champollion, C., Masson, F., Van Baelen, J., Walpersdorf, A., Chéry, J. and Doerflinger, E. GPS monitoring of the tropospheric water vapor distribution and variation during the 9 September 2002 torrential precipitation episode in the Cévennes (southern France) 2004 Journal of Geophysical Research D: Atmospheres
Vol. 109(24), pp. 1-15
article DOI
Abstract: On 8-9 September 2002, torrential rainfall and flooding hit the Gard region in southern France causing extensive damages and casualties. This is an exceptional example of a so-called Cevenol episode with 24 hour cumulative rainfall up to about 600 mm at some places and more than 200 mm over a large area (5500 km(2)). In this work we have used GPS data to determine integrated water vapor (IWV) as well as horizontal wet gradients and residuals. Using the IWV, we have monitored the evolution of the convective system associated with the rainfall from the water vapor accumulation stage through the stagnation of the convective cell and finally to the breakup of the system. Our interpretation of the GPS meteorological parameters is supported by synoptic maps, numerical weather analyses, and rain images from meteorological radars. We have evidenced from GPS data that this heavy precipitation is associated with ongoing accumulation of water vapor, even through the raining period, but that rain stopped as soon as the weather circulation pattern changed. The evolution of this event is typical in the context of the Cevenol meteorology. Furthermore, we have shown that the horizontal wet gradients help describe the heterogeneity of the water vapor field and holds information concerning the passage of the convective system. Finally, we have noticed that the residuals, which in theory should be proportional to water vapor heterogeneity, were also highly perturbed by the precipitation itself. In our conclusions we discuss the interest of a regional GPS network for monitoring and for future studies on water vapor tomography.
BibTeX:
@article{Champollion2004,
author = {Champollion, Cedric and Masson, F. and Van Baelen, J. and Walpersdorf, A. and Chéry, J. and Doerflinger, E.},
title = {GPS monitoring of the tropospheric water vapor distribution and variation during the 9 September 2002 torrential precipitation episode in the Cévennes (southern France)},
journal = {Journal of Geophysical Research D: Atmospheres},
year = {2004},
volume = {109},
number = {24},
pages = {1--15},
doi = {https://doi.org/10.1029/2004JD004897}
}

Champollion, C., Masson, F., Brenot, H., Ducrocq, V. and Walpersdorf, A. Theoretical Studies And Applications Of Regional 4D GPS Tropospheric Tomography 2004 AGU Fall Meeting Abstracts  article
BibTeX:
@article{Champollion2004b,
author = {Champollion, C and Masson, F and Brenot, H and Ducrocq, V and Walpersdorf, A},
title = {Theoretical Studies And Applications Of Regional 4D GPS Tropospheric Tomography},
journal = {AGU Fall Meeting Abstracts},
year = {2004}
}

Champollion, C., Masson, F., Bouin, M.N., Walpersdorf, A., Doerflinger, E., Bock, O. and Van Baelen, J. GPS water vapour tomography: Preliminary results from the ESCOMPTE field experiment 2005
Vol. 74(1-4)Atmospheric Research, pp. 253-274
inproceedings DOI
Abstract: Water vapour plays a major role in atmospheric processes but remains difficult to quantify due to its high variability in time and space and the sparse set of available measurements. The GPS has proved its capacity to measure the integrated water vapour at zenith with the same accuracy as other methods. Recent studies show that it is possible to quantify the integrated water vapour in the line of sight of the GPS satellite. These observations can be used to study the 3D heterogeneity of the troposphere using tomographic techniques. We develop three-dimensional tomographic software to model the three-dimensional distribution of the tropospheric water vapour from GPS data. First, the tomographic software is validated by simulations based on the realistic ESCOMPTE GPS network configuration. Without a priori information, the absolute value of water vapour is less resolved as opposed to relative horizontal variations. During the ESCOMPTE field experiment, a dense network of 17 dual frequency GPS receivers was operated for 2 weeks within a 20×20-km area around Marseille (southern France). The network extends from sea level to the top of the Etoile chain (∼700 m high). Optimal results have been obtained with time windows of 30-min intervals and input data evaluation every 15 min. The optimal grid for the ESCOMTE geometrical configuration has a horizontal step size of 0.05°×0.05° and 500 m vertical step size. Second, we have compared the results of real data inversions with independent observations. Three inversions have been compared to three successive radiosonde launches and shown to be consistent. A good resolution compared to the a priori information is obtained up to heights of 3000 m. A humidity spike at 4000-m altitude remains unresolved. The reason is probably that the signal is spread homogeneously over the whole network and that such a feature is not resolvable by tomographic techniques. The results of our pure GPS inversion show a correlation with meteorological phenomena. Our measurements could be related to the land-sea breeze. Undoubtedly, tomography has some interesting potential for the water vapour cycle studies at small temporal and spatial scales. © 2004 Elsevier B.V. All rights reserved.
BibTeX:
@inproceedings{Champollion2005a,
author = {Champollion, Cedric and Masson, F. and Bouin, M. N. and Walpersdorf, A. and Doerflinger, E. and Bock, O. and Van Baelen, J.},
title = {GPS water vapour tomography: Preliminary results from the ESCOMPTE field experiment},
booktitle = {Atmospheric Research},
year = {2005},
volume = {74},
number = {1-4},
pages = {253--274},
doi = {https://doi.org/10.1016/j.atmosres.2004.04.003}
}

Champollion, C., Flamant, C., Bock, O., Masson, F., Turner, D.D. and Weckwerth, T. Mesoscale GPS tomography applied to the 12 June 2002 convective initiation event of IHOP_2002 2009 Quarterly Journal of the Royal Meteorological Society
Vol. 135(640), pp. 645-662
article DOI URL
Abstract: The time-varying three-dimensional water vapour field derived from mesoscale Global Positioning System (GPS) tomography data is used to describe the water vapour variability in relation to the dynamics of the atmo sphere during convective initiation (CI). The paper presents the theoretical framework of GPS tomography at the mesoscale, including aspects related to the assimilation of independent data (e.g. water vapour profiles issued from meteorological balloon soundings). GPS tomography-derived water vapour density retrievals are validated against lidar, the Atmospheric Emitted Radiance Interferometer and radiosonde data, even if the short three-day period of the study prevents conclusions about the real accuracy of the GPS tomography technique. GPS tomography products are used, in synergy with surface and sounding-derived meteorological variable measurements, satellite imagery and reflectivity composites from the WSR-88D network and S-POL radar, to study environmental conditions leading to the 12 June 2002 CI event during the International H(2)O Project. On this day, CI was triggered simultaneously, shortly after 2100 UTC, in two locations along an old Outflow boundary lying east-west in the vicinity of the Oklahoma-Kansas border. The study focuses on CI to the east, which was triggered at the intersection of the outflow boundary with a distinct southwest-northeast-oriented moisture convergence line. The latter formed as the result of a cross-dryline circulation leading to the penetration of dry air meeting with the moister air mass associated with the southerly low-level flow east of the dryline. These intersecting boundaries appeared to have provided the necessary triggering mechanism for getting moist surface air parcels up to the level of free convection. Tomography-derived water vapour fields provided observational evidence of the vertical transport of water vapour above the lifting condensation level and the level of free convection to the south of and along the intersecting boundaries. Copyright (C) 2009 Royal Meteorological Society
BibTeX:
@article{Champollion2009a,
author = {Champollion, C. and Flamant, C. and Bock, O. and Masson, F. and Turner, D. D. and Weckwerth, T.},
title = {Mesoscale GPS tomography applied to the 12 June 2002 convective initiation event of IHOP_2002},
journal = {Quarterly Journal of the Royal Meteorological Society},
publisher = {Wiley-Blackwell},
year = {2009},
volume = {135},
number = {640},
pages = {645--662},
url = {http://dx.doi.org/10.1002/qj.386},
doi = {https://doi.org/10.1002/qj.386}
}

Collilieux, X. and Wöppelmann, G. Global sea-level rise and its relation to the terrestrial reference frame 2011 Journal of Geodesy
Vol. 85(1), pp. 9-22
article DOI URL
Abstract: We examined the sensitivity of estimates of global sea-level rise obtained from GPS-corrected long term tide gauge records to uncertainties in the International Terrestrial Reference Frame (ITRF) realization. A useful transfer function was established, linking potential errors in the reference frame datum (origin and scale) to resulting errors in the estimate of global sea level rise. Contrary to scale errors that are propagated by a factor of 100%, the impact of errors in the origin depends on the network geometry. The geometry of the network analyzed here resulted in an error propagation factor of 50% for the Z component of the origin, mainly due to the asymmetry in the distribution of the stations between hemispheres. This factor decreased from 50% to less than 10% as the geometry of the network improved using realistic potential stations that did not yet meet the selection criteria (e.g., record length, data availability). Conversely, we explored new constraints on the reference frame by considering forward calculations involving tide gauge records. A reference frame could be found in which the scatter of the regional sea-level rates was limited. The resulting reference frame drifted by 1.36 0.22 mm/year from the ITRF2000 origin in the Z component and by ??0.44 0.22mm/year from the ITRF2005 origin. A bound on the rate of global sea level rise of 1.2 to 1.6mm/year was derived for the past century, depending on the origin of the adopted reference frame. The upper bound is slightly lower than previous estimates of 1.8mm/year discussed in the IPCC fourth report.
BibTeX:
@article{Collilieux2011a,
author = {Collilieux, Xavier and Wöppelmann, Guy},
title = {Global sea-level rise and its relation to the terrestrial reference frame},
journal = {Journal of Geodesy},
publisher = {Springer Science backslashmathplus Business Media},
year = {2011},
volume = {85},
number = {1},
pages = {9--22},
url = {http://dx.doi.org/10.1007/s00190-010-0412-4},
doi = {https://doi.org/10.1007/s00190-010-0412-4}
}

Crusem, R. and Monfret, T. La letttre d’information RESIF n°3 Juillet 2013 2013   article
BibTeX:
@article{Crusem2013a,
author = {Crusem, René and Monfret, Tony},
title = {La letttre d’information RESIF n°3 Juillet 2013},
year = {2013}
}

D'Agostino, N., Mantenuto, S., D'Anastasio, E., Avallone, A., Barchi, M., Collettini, C., Radicioni, F., Stoppini, A. and Fastellini, G. Contemporary crustal extension in the Umbria-Marche Apennines from regional CGPS networks and comparison between geodetic and seismic deformation 2009 Tectonophysics
Vol. 476(1-2), pp. 3-12
article DOI URL
Abstract: Here we report the results of the analysis of a GPS velocity field in the Umbria-Marche Apennines (central Italy) obtained from the integration of diverse geodetic networks. The velocity field obtained shows a high degree of consistency both spatially and in terms of comparison with independent information, despite the limited time span of some GPS stations. Starting from the velocity field we derive a continuous strain rate field applying a spline interpolation technique which provide a smooth estimate of the deformation field. The main feature of the resulting strain rate field is a continuous high (>50 nanostrain/year) strain rate belt coincident with the area of largest historical and instrumental seismic release. The model directions of the principal axes agree with geological and seismological information indicating NE-SW extension. We transform the strain rate field into geodetic moment rate using the Kostrov formula to evaluate the potential seismic activity of the region and compare it with actual seismic release in the last 720 years from Mw>5.5 earthquakes. This comparison highlights a large possible deficit in the seismic release with respect to the overall potential seismic activity, particularly concentrated in the northern part of the study area. This discrepancy can be resolved with either a large amount of seismicity to be released in the near future or significant aseismic slip and deformation. ?? 2008 Elsevier B.V. All rights reserved.
BibTeX:
@article{DAgostino2009a,
author = {D'Agostino, N. and Mantenuto, S. and D'Anastasio, E. and Avallone, A. and Barchi, M. and Collettini, C. and Radicioni, F. and Stoppini, A. and Fastellini, G.},
title = {Contemporary crustal extension in the Umbria-Marche Apennines from regional CGPS networks and comparison between geodetic and seismic deformation},
journal = {Tectonophysics},
publisher = {Elsevier BV},
year = {2009},
volume = {476},
number = {1-2},
pages = {3--12},
url = {http://dx.doi.org/10.1016/j.tecto.2008.09.033},
doi = {https://doi.org/10.1016/j.tecto.2008.09.033}
}

Delrieu, G., Nicol, J., Yates, E., Kirstetter, P.-E., Creutin, J.-D., Anquetin, S., Obled, C., Saulnier, G.-M., Ducrocq, V., Gaume, E., Payrastre, O., Andrieu, H., Ayral, P.-A., Bouvier, C., Neppel, L., Livet, M., Lang, M., Du-Châtelet, J.P., Walpersdorf, A. and Wobrock, W. The Catastrophic Flash-Flood Event of 8–9 September 2002 in the Gard Region, France: A First Case Study for the Cévennes–Vivarais Mediterranean Hydrometeorological Observatory 2005 Journal of Hydrometeorology
Vol. 6(1), pp. 34-52
article DOI URL
Abstract: Abstract The Cévennes–Vivarais Mediterranean Hydrometeorological Observatory (OHM-CV) is a research initiative aimed at improving the understanding and modeling of the Mediterranean intense rain events that frequently result in devastating flash floods in southern France. A primary objective is to bring together the skills of meteorologists and hydrologists, modelers and instrumentalists, researchers and practitioners, to cope with these rather unpredictable events. In line with previously published flash-flood monographs, the present paper aims at documenting the 8–9 September 2002 catastrophic event, which resulted in 24 casualties and an economic damage evaluated at 1.2 billion euros (i.e., about 1 billion U.S. dollars) in the Gard region, France. A description of the synoptic meteorological situation is first given and shows that no particular precursor indicated the imminence of such an extreme event. Then, radar and rain gauge analyses are used to assess the magnitude of the rain event, which was pa...
BibTeX:
@article{Delrieu2005a,
author = {Delrieu, Guy and Nicol, John and Yates, Eddy and Kirstetter, Pierre-Emmanuel and Creutin, Jean-Dominique and Anquetin, Sandrine and Obled, Charles and Saulnier, Georges-Marie and Ducrocq, Véronique and Gaume, Eric and Payrastre, Olivier and Andrieu, Hervé and Ayral, Pierre-Alain and Bouvier, Christophe and Neppel, Luc and Livet, Marc and Lang, Michel and Du-Châtelet, Jacques Parent and Walpersdorf, Andrea and Wobrock, Wolfram},
title = {The Catastrophic Flash-Flood Event of 8–9 September 2002 in the Gard Region, France: A First Case Study for the Cévennes–Vivarais Mediterranean Hydrometeorological Observatory},
journal = {Journal of Hydrometeorology},
year = {2005},
volume = {6},
number = {1},
pages = {34--52},
url = {http://journals.ametsoc.org/doi/full/10.1175/JHM-400.1},
doi = {https://doi.org/10.1175/JHM-400.1}
}

Devoti, R., Esposito, A., Pietrantonio, G., Pisani, A.R. and Riguzzi, F. Evidence of large scale deformation patterns from GPS data in the Italian subduction boundary 2011 Earth and Planetary Science Letters
Vol. 311(3-4), pp. 230-241
article DOI URL
Abstract: We present the velocity field in Italy derived from over 300 continuous GPS stations operated in the 1998-2009 time span. The GPS network maps the whole country with a mean inter-site distance of about 50km and provides a valuable source of data to study the ongoing deformation processes in the central Mediterranean. The estimated horizontal and vertical velocity fields show major significant features and also less known second-order kinematic features. A general uplift characterizes the whole Apennines and Alpine belts that follow the topographic ridge, whereas the Po Plain shows a gradually increasing subsidence from west to east. The Apennines belt displays a distinctive extension (50-80 10-9yr-1) while compressive tectonic regimes characterize northern Sicily, eastern Alps and the northeast front of the northern Apennines (25-50 10-9yr-1). Second-order deformation patterns, on large scale wavelength (˜100km) have been detected on the accretionary prism of central and southern Apennines that are highly correlated with other geophysical data (Vp anomalies, seismic anisotropy, etc.) and related to deep rooted sections (70-100km), marked by different subduction regimes. Apparently at this scale-length the observed deformations are governed by the lithosphere as a whole. We interpret these deformations as a result of different subduction mechanisms, such as variations of the subduction rollback velocity affecting different segments of the subduction zone and/or to mantle flows in proximity of the slab edges. Further south, in central-southern Sicily, we detect a contraction of (-1.1±0.2) mm/yr that probably accommodates part of the Africa-Eurasia convergence on the outer thrust front of the Apennines-Maghrebides belt. This hypothesis agrees with an independent analysis of the seismicity associated to the Sicilian Basal Thrust, thought to be still active. The ITRF2005 estimates of the new GPS velocity field are available also in SINEX format as supplementary file S1. © 2011 Elsevier B.V.
BibTeX:
@article{Devoti2011a,
author = {Devoti, Roberto and Esposito, Alessandra and Pietrantonio, Grazia and Pisani, Anna Rita and Riguzzi, Federica},
title = {Evidence of large scale deformation patterns from GPS data in the Italian subduction boundary},
journal = {Earth and Planetary Science Letters},
publisher = {Elsevier BV},
year = {2011},
volume = {311},
number = {3-4},
pages = {230--241},
url = {http://dx.doi.org/10.1016/j.epsl.2011.09.034},
doi = {https://doi.org/10.1016/j.epsl.2011.09.034}
}

Devoti, R., D'Agostino, N., Serpelloni, E., Pietrantonio, G., Riguzzi, F., Avallone, A., Cavaliere, A., Cheloni, D., Cecere, G., D'Ambrosio, C. and Others A Combined Velocity Field of the Mediterranean Region 2017 Annals of Geophysics
Vol. 60(2), pp. 215
article DOI
BibTeX:
@article{Devoti2017a,
author = {Devoti, Roberto and D'Agostino, Nicola and Serpelloni, Enrico and Pietrantonio, Grazia and Riguzzi, Federica and Avallone, Antonio and Cavaliere, Adriano and Cheloni, Daniele and Cecere, Giampaolo and D'Ambrosio, Ciriaco and Others},
title = {A Combined Velocity Field of the Mediterranean Region},
journal = {Annals of Geophysics},
year = {2017},
volume = {60},
number = {2},
pages = {215},
doi = {https://doi.org/10.4401/ag-7059}
}

Doulkeridis, C., Vlachou, A., Kotidis, Y. and Vazirgiannis, M. Peer-to-peer similarity search in metric spaces 2007
Vol. 2(iii)Proceedings of the 33rd international conference on Very Large Databases, pp. 986-997
incollection DOI URL
Abstract: This paper addresses the efficient processing of similarity queries in metric spaces, where data is horizontally distributed across a P2P network. The proposed approach does not rely on arbitrary data movement, hence each peer joining the network autonomously ...
BibTeX:
@incollection{Doulkeridis2007a,
author = {Doulkeridis, Christos and Vlachou, Akrivi and Kotidis, Yannis and Vazirgiannis, Michalis},
title = {Peer-to-peer similarity search in metric spaces},
booktitle = {Proceedings of the 33rd international conference on Very Large Databases},
publisher = {Springer Science backslashmathplus Business Media},
year = {2007},
volume = {2},
number = {iii},
pages = {986--997},
url = {http://portal.acm.org/citation.cfm?id=1325851.1325962},
doi = {https://doi.org/10.1007/978-1-4614-}
}

Ducrocq, V., Belamari, S., Boudevillain, B., Bousquet, O., Cocquerez, P., Doerenbecher, a., Drobinski, P., Flamant, C., Labatut, L., Lambert, D., Nuret, M., Richard, E., Roussot, O., Testor, P., Arbogast, P., Ayral, P.-a., Baelen, J.V., Basdevant, C., Boichard, J.-L., Bourras, D., Bouvier, C., Bouin, M.-N., Bock, O., Braud, I., Champollion, C., Coppola, L., Coquillat, S., Defer, E., Delanoe, J., Delrieu, G., Didon-Lescot, J.-F., Durand, P., Estournel, C., Fourrié, N., Garrouste, O., Giordani, H., Coz, J.L., Michel, Y., Nuissier, O., Roberts, G., Said, F., Schwarzenboeck, a., Sellegri, K., Taupier-Letage, I. and Vandervaere, J.-P. HyMeX, les campagnes de mesures : focus sur les événements extrêmes en Méditerranée 2013 La Météorologie
Vol. 8(80), pp. 37
article DOI URL
BibTeX:
@article{Ducrocq2013a,
author = {Ducrocq, V. and Belamari, S. and Boudevillain, B. and Bousquet, O. and Cocquerez, P. and Doerenbecher, a. and Drobinski, P. and Flamant, C. and Labatut, L. and Lambert, D. and Nuret, M. and Richard, E. and Roussot, O. and Testor, P. and Arbogast, P. and Ayral, P.-a. and Baelen, J. Van and Basdevant, C. and Boichard, J.-L. and Bourras, D. and Bouvier, C. and Bouin, M.-N. and Bock, O. and Braud, I. and Champollion, C. and Coppola, L. and Coquillat, S. and Defer, E. and Delanoe, J. and Delrieu, G. and Didon-Lescot, J.-F. and Durand, P. and Estournel, C. and Fourrié, N. and Garrouste, O. and Giordani, H. and Coz, J. Le and Michel, Y. and Nuissier, O. and Roberts, G. and Said, F. and Schwarzenboeck, a. and Sellegri, K. and Taupier-Letage, I. and Vandervaere, J.-P.},
title = {HyMeX, les campagnes de mesures : focus sur les événements extrêmes en Méditerranée},
journal = {La Météorologie},
publisher = {INIST-CNRS},
year = {2013},
volume = {8},
number = {80},
pages = {37},
url = {http://hdl.handle.net/2042/48793},
doi = {https://doi.org/10.4267/2042/48793}
}

Feng, G., Jin, S. and Zhang, T. Coastal sea level changes in Europe from GPS, tide gauge, satellite altimetry and GRACE, 1993-2011 2013 Advances in Space Research
Vol. 51(6), pp. 1019-1028
article DOI URL
Abstract: Sea level changes are threatening the human living environments, particularly along the European Coasts with highly dense population. In this paper, coastal sea level changes in western and southern Europe are investigated for the period 1993-2011 using Global Positioning System (GPS), Tide Gauge (TG), Satellite Altimetry (SA), Gravity Recovery and Climate Experiment (GRACE) and geophysical models. The mean secular trend is 2.26 ± 0.52 mm/y from satellite altimetry, 2.43 ± 0.61 mm/y from TG+GPS and 1.99 ± 0.67 mm/y from GRACE mass plus steric components, which have a remarkably good agreement. For the seasonal variations, annual amplitudes of satellite altimetry and TG+GPS results are almost similar, while GRACE Mass+Steric results are a little smaller. The annual phases agree remarkably well for three independent techniques. The annual cycle is mainly driven by the steric contributions, while the annual phases of non-steric (mass component) sea level changes are almost a half year later than the steric sea level changes.
BibTeX:
@article{Feng2013a,
author = {Feng, Guiping and Jin, S. and Zhang, T.},
title = {Coastal sea level changes in Europe from GPS, tide gauge, satellite altimetry and GRACE, 1993-2011},
journal = {Advances in Space Research},
publisher = {Elsevier BV},
year = {2013},
volume = {51},
number = {6},
pages = {1019--1028},
url = {http://dx.doi.org/10.1016/j.asr.2012.09.011},
doi = {https://doi.org/10.1016/j.asr.2012.09.011}
}

Ferenc, M., Nicolas, J., van Dam, T., Polidori, L., Rigo, A. and Vernant, P. An estimate of the influence of loading effects on tectonic velocities in the Pyrenees 2014 Studia Geophysica et Geodaetica
Vol. 58(1), pp. 56-75
article DOI URL
BibTeX:
@article{Ferenc2014a,
author = {Ferenc, Marcell and Nicolas, Joelle and van Dam, Tonie and Polidori, Laurent and Rigo, Alexis and Vernant, Philippe},
title = {An estimate of the influence of loading effects on tectonic velocities in the Pyrenees},
journal = {Studia Geophysica et Geodaetica},
publisher = {Springer Science backslashmathplus Business Media},
year = {2014},
volume = {58},
number = {1},
pages = {56--75},
url = {http://dx.doi.org/10.1007/s11200-012-0458-2},
doi = {https://doi.org/10.1007/s11200-012-0458-2}
}

Fuhrmann, T., Luo, X., Knöpfler, A. and Mayer, M. Generating statistically robust multipath stacking maps using congruent cells 2014 GPS Solutions
Vol. 19(1), pp. 83-92
article DOI URL
Abstract: Multipath effects caused by reflections in the near-field and far-field of a GNSS antenna represent a major error source in static and kinematic GNSS positioning applications. Since these effects are strongly site-specific, a generally valid and practicable analytical multipath model is still lacking. In contrast, using GNSS carrier phase observation residuals, the multipath stacking (MPS) methods are able to take site-specific conditions into account. We propose an advanced approach to performing residual-based MPS in the space domain. Being superior to most conventional attempts in which stacking cells have a fixed azimuthal resolution, our suggested method makes use of congruent cells and rigorous statistical assessments in terms of outlier detection and significance evaluation of the stacked values. The advanced stacking approach is applied to representative phase residuals from static precise point positioning. The results show that the use of congruent cells allows for MPS at high elevation angles and with a fine spatial resolution. Applying the resulting MPS maps at the residual level, both near-field and far-field effects at high and low elevation angles, respectively, can be significantly mitigated. In comparison with the conventional approach, the advanced one enables a larger reduction of about 20 % in the SD of residuals.
BibTeX:
@article{Fuhrmann2014a,
author = {Fuhrmann, Thomas and Luo, Xiaoguang and Knöpfler, Andreas and Mayer, Michael},
title = {Generating statistically robust multipath stacking maps using congruent cells},
journal = {GPS Solutions},
publisher = {Springer Science backslashmathplus Business Media},
year = {2014},
volume = {19},
number = {1},
pages = {83--92},
url = {http://dx.doi.org/10.1007/s10291-014-0367-7},
doi = {https://doi.org/10.1007/s10291-014-0367-7}
}

Fund, F., Fund, F., Morel, L. and Mocquet, A. A discussion of height reductions for Zenith Hydrostatic Delays derived from weather models 2011 Journal of Applied Geodesy
Vol. 5(2), pp. 71-80
article DOI URL
Abstract: Abstract Accurate a priori Zenith Hydrostatic Delays (ZHDs) are required during the processing of space geodetic observations. The data provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) are routinely processed and translated in terms of ZHDs by the Vienna University of Technology. The usual way to compute gridded ZHDs at a particular location is to correct the four nearest nodes of the grid for their difference in height with respect to the site height and to then interpolate these reduced values. This paper compares and discusses the performance achieved by five methods of reduction that have been proposed in the literature. The interpolated ZHD values are compared with the site-specific ones for a global network of 363 sites over a three-year period. The methods that only use vertical profiles of atmospheric pressure lead to annual signals that are correlated with ground temperature, while the methods that take temperature into account do not contain such annual signals. The reduction methods that use a constant temperature lead to errors of ˜2 mm in terms of equivalent height. We also find that the a posteriori errors of the reduced gridded ZHDs are strongly correlated with the pressure over temperature ratio. We recommend that gridded ZHDs be reduced with the combination of both pressure and temperature when processing space geodetic observations. Abstract Accurate a priori Zenith Hydrostatic Delays (ZHDs) are required during the processing of space geodetic observations. The data provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) are routinely processed and translated in terms of ZHDs by the Vienna University of Technology. The usual way to compute gridded ZHDs at a particular location is to correct the four nearest nodes of the grid for their difference in height with respect to the site height and to then interpolate these reduced values. This paper compares and discusses the performance achieved by five methods of reduction that have been proposed in the literature. The interpolated ZHD values are compared with the site-specific ones for a global network of 363 sites over a three-year period. The methods that only use vertical profiles of atmospheric pressure lead to annual signals that are correlated with ground temperature, while the methods that take temperature into account do not contain such annual signals. The reduction methods that use a constant temperature lead to errors of ˜2 mm in terms of equivalent height. We also find that the a posteriori errors of the reduced gridded ZHDs are strongly correlated with the pressure over temperature ratio. We recommend that gridded ZHDs be reduced with the combination of both pressure and temperature when processing space geodetic observations.
BibTeX:
@article{Fund2011,
author = {Fund, F. and Fund, F. and Morel, L. and Mocquet, A.},
title = {A discussion of height reductions for Zenith Hydrostatic Delays derived from weather models},
journal = {Journal of Applied Geodesy},
publisher = {Walter de Gruyter GmbH},
year = {2011},
volume = {5},
number = {2},
pages = {71--80},
url = {citeulike-article-id:9649443backslashnhttp://dx.doi.org/10.1515/jag.2011.006},
doi = {https://doi.org/10.1515/jag.2011.006}
}

Fund, F., Morel, L., Mocquet, A. and Boehm, J. Assessment of ECMWF-derived tropospheric delay models within the EUREF Permanent Network 2011 GPS Solutions
Vol. 15(1), pp. 39-48
article DOI URL
BibTeX:
@article{Fund2011b,
author = {Fund, F. and Morel, L. and Mocquet, A. and Boehm, J.},
title = {Assessment of ECMWF-derived tropospheric delay models within the EUREF Permanent Network},
journal = {GPS Solutions},
publisher = {Springer Science backslashmathplus Business Media},
year = {2011},
volume = {15},
number = {1},
pages = {39--48},
url = {http://dx.doi.org/10.1007/s10291-010-0166-8},
doi = {https://doi.org/10.1007/s10291-010-0166-8}
}

Fund, F., Morel, L. and Mocquet, A. Assessment of the FES2004 Derived OTL Model in the West of France and Preliminary Results About Impacts of Tropospheric Models 2012
Vol. 136Geodesy for Planet Earth, pp. 573-579
incollection DOI URL
BibTeX:
@incollection{Fund2012a,
author = {Fund, F and Morel, L and Mocquet, A},
title = {Assessment of the FES2004 Derived OTL Model in the West of France and Preliminary Results About Impacts of Tropospheric Models},
booktitle = {Geodesy for Planet Earth},
publisher = {Springer Science backslashmathplus Business Media},
year = {2012},
volume = {136},
pages = {573--579},
url = {http://dx.doi.org/10.1007/978-3-642-20338-1_70},
doi = {https://doi.org/10.1007/978-3-642-20338-1%7B%5C_%7D70}
}

Garate, J., Martin-Davila, J., Khazaradze, G., Echeverria, A., Asensio, E., Gil, A.J., de Lacy, M.C., Armenteros, J.A., Ruiz, A.M., Gallastegui, J., Alvarez-Lobato, F., Ayala, C., Rodr\iguez-Caderot, G., Galindo-Zald\ivar, J., Rimi, A. and Harnafi, M. Topo-Iberia project: CGPS crustal velocity field in the Iberian Peninsula and Morocco 2015 GPS Solutions
Vol. 19(2), pp. 287-295
article DOI URL
Abstract: A new Continuous GPS network was installed under the umbrella of a Research Project called “Geociencias en Iberia: Estudios integrados de topograf\ia y evolución 4D (Topo-Iberia)”, to improve understanding of kinematic behavior of the Iberian Peninsula region. Here we present a velocity field based on the analysis of the four years of data from the 25 stations constituting the network, which were analyzed by three different analysis groups contributing to the project. Different geodetic software packages (GIPSY–OASIS, Bernese and GAMIT) as well as different approaches were used to estimate rates of present-day crustal deformation in the Iberian Peninsula and Morocco. In order to ensure the consistency of the velocity fields determined by the three groups, the velocities obtained by each Analysis Centre were transformed into a common Eurasia Reference Frame. After that, the strain rate field was calculated. The results put in evidence more prominent residual motions in Morocco and southern-most part of the Iberian Peninsula. In particular, the dilatation and shear strain rates reach their maximum values in the central Betics and northern Alboran Sea. A small region of high shear strain rate is observed in the east-central part of the peninsula and another deformation focus is located around the Strait of Gibraltar and the Gulf of Cadiz.
BibTeX:
@article{Garate2015a,
author = {Garate, J. and Martin-Davila, J. and Khazaradze, G. and Echeverria, A. and Asensio, E. and Gil, A. J. and de Lacy, M. C. and Armenteros, J. A. and Ruiz, A. M. and Gallastegui, J. and Alvarez-Lobato, F. and Ayala, C. and Rodr\iguez-Caderot, G. and Galindo-Zald\ivar, J. and Rimi, A. and Harnafi, M.},
title = {Topo-Iberia project: CGPS crustal velocity field in the Iberian Peninsula and Morocco},
journal = {GPS Solutions},
publisher = {Springer Science backslashmathplus Business Media},
year = {2015},
volume = {19},
number = {2},
pages = {287--295},
url = {http://dx.doi.org/10.1007/s10291-014-0387-3},
doi = {https://doi.org/10.1007/s10291-014-0387-3}
}

Gardi, A., Baize, S. and Scotti, O. Present-day vertical isostatic readjustment of the Western Alps revealed by numerical modelling and geodetic and seismotectonic data 2010 Advances in Interpretation of Geological Processes: Refinement of Multi-Scale Data and Integration in Numerical Modelling
Vol. 332(1), pp. 115-128
article DOI URL
Abstract: The active tectonics of the Western Alps reveals contrasting regimes: ongoing extension at the heart of the chain and transpression-compression at its external sectors. The active processes currently affecting this region are still a matter of debate. The classical models proposed in the literature invoke: Eurasia-Adria plate collision, counterclockwise motion of the Adria microplate, slab retreat of the subducted continental lithosphere and slab-detachment. More recently, several authors prefer the hypothesis of tectonics driven by isostasy-buoyancy forces. To better understand the influence of these processes on the velocity, strain and stress fields at the surface and in the crust, we developed 2D viscoelastic numerical models along a vertical cross-section perpendicular to the Western Alps. We run our models with different driving forces in order to investigate, one by one, the geodynamic processes proposed in the literature. Results are compared with available geodetic, geological and seismotectonic data. In order to bring into coincidence model predictions and observations, an important vertical isostatic readjustment must be included in the modelling, together with a slight horizontal compression (0.5 mm year(-1)), probably due to Africa-Eurasia convergence. We show that the subduction process in this Alpine region is likely to be dead and that buoyancy forces may be dominating the present-day tectonics.
BibTeX:
@article{Gardi2010a,
author = {Gardi, A and Baize, S and Scotti, O},
title = {Present-day vertical isostatic readjustment of the Western Alps revealed by numerical modelling and geodetic and seismotectonic data},
journal = {Advances in Interpretation of Geological Processes: Refinement of Multi-Scale Data and Integration in Numerical Modelling},
publisher = {Geological Society of London},
year = {2010},
volume = {332},
number = {1},
pages = {115--128},
url = {://WOS:000288760600009},
doi = {https://doi.org/10.1144/sp332.8}
}

Gouriou, T., Mart\in M\iguez, B. and Wöppelmann, G. Reconstruction of a two-century long sea level record for the Pertuis d'Antioche (France) 2013 Continental Shelf Research
Vol. 61-62, pp. 31-40
article DOI URL
Abstract: This paper describes the work of sea level data rescue, digitization, reduction to a common vertical reference and quality control leading to the reconstruction of a time series for the Atlantic NW coast of France (Pertuis d'Antioche). A total of 14 sea level data sets were merged to build a consistent composite time series of monthly and annual mean sea levels spanning 188 years (1824-2011).The estimation of a linear trend for this time series yields a relative mean sea level rise for the region of 1.3±0.1mmyr-1 for the whole study period, and 1.9±0.2mmyr-1 for the 20th century, consistent with previous studies in the region. This work evidences the importance of data archaeology in the pursuing of historical information useful for sea level studies, which can be relevant for climate research and coastal management amongst other applications. © 2013 Elsevier Ltd.
BibTeX:
@article{Gouriou2013a,
author = {Gouriou, Thomas and Mart\in M\iguez, Belén and Wöppelmann, Guy},
title = {Reconstruction of a two-century long sea level record for the Pertuis d'Antioche (France)},
journal = {Continental Shelf Research},
publisher = {Elsevier BV},
year = {2013},
volume = {61-62},
pages = {31--40},
doi = {https://doi.org/10.1016/j.csr.2013.04.028}
}

Jin, R., Jin, S. and Feng, G. M_DCB: Matlab code for estimating GNSS satellite and receiver differential code biases 2012 GPS Solutions
Vol. 16(4), pp. 541-548
article DOI URL
Abstract: Global navigation satellite systems (GNSS) have been widely used to monitor variations in the earth's ionosphere by estimating total electron content (TEC) using dual-frequency observations. Differential code biases (DCBs) are one of the important error sources in estimating precise TEC from GNSS data. The International GNSS Service (IGS) Analysis Centers have routinely provided DCB estimates for GNSS satellites and IGS ground receivers, but the DCBs for regional and local network receivers are not provided. Furthermore, the DCB values of GNSS satellites or receivers are assumed to be constant over 1 day or 1 month, which is not always the case. We describe Matlab code to estimate GNSS satellite and receiver DCBs for time intervals from hours to days; the software is called M_DCB. The DCBs of GNSS satellites and ground receivers are tested and evaluated using data from the IGS GNSS network. The estimates from M_DCB show good agreement with the IGS Analysis Centers with a mean difference of less than 0. 7 ns and an RMS of less than 0. 4 ns, even for a single station DCB estimate. © 2012 Springer-Verlag.
BibTeX:
@article{Jin2012a,
author = {Jin, Rui and Jin, Shuanggen and Feng, Guiping},
title = {M_DCB: Matlab code for estimating GNSS satellite and receiver differential code biases},
journal = {GPS Solutions},
publisher = {Springer Science backslashmathplus Business Media},
year = {2012},
volume = {16},
number = {4},
pages = {541--548},
url = {http://dx.doi.org/10.1007/s10291-012-0279-3},
doi = {https://doi.org/10.1007/s10291-012-0279-3}
}

King, M.A., Keshin, M., Whitehouse, P.L., Thomas, I.D., Milne, G. and Riva, R.E.M. Regional biases in absolute sea-level estimates from tide gauge data due to residual unmodeled vertical land movement 2012 Geophysical Research Letters
Vol. 39(14), pp. n/a--n/a
article DOI URL
Abstract: The only vertical land movement signal routinely corrected for when estimating absolute sea-level change from tide gauge data is that due to glacial isostatic adjustment (GIA). We compare modeled GIA uplift (ICE-5G + VM2) with vertical land movement at ∼300 GPS stations located near to a global set of tide gauges, and find regionally coherent differences of commonly ±0.5–2 mm/yr. Reference frame differences and signal due to present-day mass trends cannot reconcile these differences. We examine sensitivity to the GIA Earth model by fitting to a subset of the GPS velocities and find substantial regional sensitivity, but no single Earth model is able to reduce the disagreement in all regions. We suggest errors in ice history and neglected lateral Earth structure dominate model-data differences, and urge caution in the use of modeled GIA uplift alone when interpreting regional- and global- scale absolute (geocentric) sea level from tide gauge data.
BibTeX:
@article{King2012a,
author = {King, Matt A. and Keshin, Maxim and Whitehouse, Pippa L. and Thomas, Ian D. and Milne, Glenn and Riva, Riccardo E M},
title = {Regional biases in absolute sea-level estimates from tide gauge data due to residual unmodeled vertical land movement},
journal = {Geophysical Research Letters},
publisher = {Wiley-Blackwell},
year = {2012},
volume = {39},
number = {14},
pages = {n/a----n/a},
url = {http://dx.doi.org/10.1029/2012gl052348},
doi = {https://doi.org/10.1029/2012GL052348}
}

Koulali, A., Ouazar, D., Tahayt, A., King, R.W., Vernant, P., Reilinger, R.E., McClusky, S., Mourabit, T., Davila, J.M. and Amraoui, N. New GPS constraints on active deformation along the Africa-Iberia plate boundary 2011 Earth and Planetary Science Letters
Vol. 308(1-2), pp. 211-217
article DOI URL
Abstract: We use velocities from 65 continuous stations and 31 survey-mode GPS sites as well as kinematic modeling to investigate present day deformation along the Africa-Iberia plate boundary zone in the western Mediterranean region. The GPS velocity field shows southwestward motion of the central part of the Rif Mountains in northern Morocco with respect to Africa varying between 3.5 and 4.0. mm/yr, consistent with prior published results. Stations in the southwestern part of the Betic Mountains of southern Spain move west-southwest with respect to Eurasia (˜ 2-3. mm/yr). The western component of Betics motion is consistent with partial transfer of Nubia-Eurasia plate motion into the southern Betics. The southward component of Betics motion with respect to Iberia is kinematically consistent with south to southwest motion of the Rif Mountains with respect to Africa. We use block modeling, constrained by mapped surface faults and seismicity to estimate the geometry and rates of strain accumulation on plate boundary structures. Our preferred plate boundary geometry includes one block between Iberia and Africa including the SW Betics, Alboran Sea, and central Rif. This geometry provides a good fit to the observed motions, suggesting a wide transpressive boundary in the westernmost Mediterranean, with deformation mainly accommodated by the Gloria-Azores fault system to the West and the Rif-Tell lineament to the East. Block boundaries encompass aspects of earlier interpretations suggesting three main deformation styles: (i) extension along the NE-SW trending Trans-Alboran shear zone, (ii) dextral strike-slip in the Betics corresponding to a well defined E-W seismic lineament, and (iii) right lateral strike-slip motion extending West to the Azores and right-lateral motion with compression extending East along the Algerian Tell. We interpret differential motion in the Rif-Alboran-Betic system to be driven both by surface processes related the Africa-Eurasia oblique convergence and sub-crustal dynamic processes associated with the long history of subduction of the Neotethys ocean lithosphere. The dextral slip identified in the Betic Mountains in Southern Spain may be related to the offshore fault that produced the Great 1755 Lisbon Earthquake, and as such may represent a significant seismic hazard for the West Mediterranean region. © 2011 Elsevier B.V.
BibTeX:
@article{Koulali2011a,
author = {Koulali, A. and Ouazar, D. and Tahayt, A. and King, R. W. and Vernant, P. and Reilinger, R. E. and McClusky, S. and Mourabit, T. and Davila, J. M. and Amraoui, N.},
title = {New GPS constraints on active deformation along the Africa-Iberia plate boundary},
journal = {Earth and Planetary Science Letters},
publisher = {Elsevier BV},
year = {2011},
volume = {308},
number = {1-2},
pages = {211--217},
url = {http://dx.doi.org/10.1016/j.epsl.2011.05.048},
doi = {https://doi.org/10.1016/j.epsl.2011.05.048}
}

Labbouz, L., Van Baelen, J., Tridon, F., Reverdy, M., Hagen, M., Bender, M., Dick, G., Gorgas, T. and Planche, C. Precipitation on the lee side of the Vosges Mountains: Multi-instrumental study of one case from the COPS campaign 2013 Meteorologische Zeitschrift
Vol. 22(4), pp. 413-432
article DOI URL
BibTeX:
@article{Labbouz2013a,
author = {Labbouz, L. and Van Baelen, J. and Tridon, F. and Reverdy, M. and Hagen, M. and Bender, M. and Dick, G. and Gorgas, T. and Planche, C.},
title = {Precipitation on the lee side of the Vosges Mountains: Multi-instrumental study of one case from the COPS campaign},
journal = {Meteorologische Zeitschrift},
publisher = {Schweizerbart},
year = {2013},
volume = {22},
number = {4},
pages = {413--432},
url = {http://openurl.ingenta.com/content/xref?genre=article&issn=0941-2948&volume=22&issue=4&spage=413},
doi = {https://doi.org/10.1127/0941-2948/2013/0413}
}

Mahfouf, J.F., Ahmed, F., Moll, P. and Teferle, F.N. Assimilation of zenith total delays in the AROME France convective scale model: A recent assessment 2015 Tellus, Series A: Dynamic Meteorology and Oceanography
Vol. 67(1), pp. 1-20
article DOI URL
BibTeX:
@article{Mahfouf2015a,
author = {Mahfouf, Jean Francois and Ahmed, Furqan and Moll, Patrick and Teferle, Felix N.},
title = {Assimilation of zenith total delays in the AROME France convective scale model: A recent assessment},
journal = {Tellus, Series A: Dynamic Meteorology and Oceanography},
publisher = {Co-Action Publishing},
year = {2015},
volume = {67},
number = {1},
pages = {1--20},
url = {http://dx.doi.org/10.3402/tellusa.v67.26106},
doi = {https://doi.org/10.3402/tellusa.v67.26106}
}

Mayer, M., Knöpfler, A., Heck, B., Masson, F., Ulrich, P. and Ferhat, G. GURN (GNSS upper Rhine Graben network): Research goals and first results of a transnational geo-scientific network 2012
Vol. 136International Association of Geodesy Symposia, pp. 673-681
incollection DOI URL
BibTeX:
@incollection{Mayer2012a,
author = {Mayer, M. and Knöpfler, A. and Heck, B. and Masson, F. and Ulrich, P. and Ferhat, G.},
title = {GURN (GNSS upper Rhine Graben network): Research goals and first results of a transnational geo-scientific network},
booktitle = {International Association of Geodesy Symposia},
publisher = {Springer Science backslashmathplus Business Media},
year = {2012},
volume = {136},
pages = {673--681},
doi = {https://doi.org/10.1007/978-3-642-20338-1%7B%5C_%7D83}
}

MAZZOTTI, S., Déprez, A., Henrion, E., MASSON, C., Masson, F., Menut, J.-L., Métois, M., Nocquet, J.M., Rolland, L., Sakic, P., Socquet, A., Santamaria-Gomez, A., Valty, P., Vergnolle, M. and VERNANT, P. Comparative analysis of synthetic GNSS time series - Bias and precision of velocity estimations 2020 School: RESIF  techreport URL
BibTeX:
@techreport{MAZZOTTI2020,
author = {MAZZOTTI, Stephane and Déprez, Aline and Henrion, Eric and MASSON, Christine and Masson, Frédéric and Menut, Jean-Luc and Métois, Marianne and Nocquet, Jean Matthieu and Rolland, Lucie and Sakic, Pierre and Socquet, Anne and Santamaria-Gomez, Alvaro and Valty, Pierre and Vergnolle, Mathilde and VERNANT, Philippe},
title = {Comparative analysis of synthetic GNSS time series - Bias and precision of velocity estimations},
school = {RESIF},
year = {2020},
url = {https://hal.archives-ouvertes.fr/hal-02460380}
}

Morel, L., Pottiaux, E., Durand, F., Fund, F., Boniface, K., De Oliveira, P.S. and Van Baelen, J. Validity and behaviour of tropospheric gradients estimated by GPS in Corsica 2015 Advances in Space Research
Vol. 55(1), pp. 135-149
article DOI URL
Abstract: Estimation of tropospheric gradients in GNSS data processing is a well-known technique to improve positioning (e.g. Bar-Sever et al., 1998; Chen and Herring, 1997). More recently, several authors also focused on the estimation of such parameters for meteorological studies and demonstrated their potential benefits (e.g. Champollion et al., 2004). Today, they are routinely estimated by several global and regional GNSS analysis centres but they are still not yet used for operational meteorology. This paper discusses the physical meaning of tropospheric gradients estimated from GPS observations recorded in 2011 by 13 permanent stations located in Corsica Island (a French Island in the western part of Italy). Corsica Island is a particularly interesting location for such study as it presents a significant environmental contrast between the continent and the sea, as well as a steep topography. Therefore, we estimated Zenith Total Delay (ZTD) and tropospheric gradients using two software: GAMIT/GLOBK (GAMIT version 10.5) and GIPSY-OASIS II version 6.1. Our results are then compared to radiosonde observations and to the IGS final troposphere products. For all stations we found a good agreement between the ZWD estimated by the two software (the mean of the ZWD differences is 1 mm with a standard deviation of 6 mm) but the tropospheric gradients are in less good agreement (the mean of the gradient differences is 0.1 mm with a standard deviation of 0.7 mm), despite the differences in the processing strategy (double-differences for GAMIT/GLOBK versus zero-difference for GIPSY-OASIS). We also observe that gradient amplitudes are correlated with the seasonal behaviour of the humidity. Like ZWD estimates, they are larger in summer than in winter. Their directions are stable over the time but not correlated with the IWV anomaly observed by ERA-Interim. Tropospheric gradients observed at many sites always point to inland throughout the year. These preferred directions are almost opposite to the largest slope of the local topography as derived from the world Digital Elevation Model ASTER GDEM v2. These first results give a physical meaning to gradients but the origin of such directions need further investigations.
BibTeX:
@article{Morel2015a,
author = {Morel, Laurent and Pottiaux, Eric and Durand, Fr??d??ric and Fund, Fran??ois and Boniface, Karen and De Oliveira, Paulo Sergio and Van Baelen, Jo??l},
title = {Validity and behaviour of tropospheric gradients estimated by GPS in Corsica},
journal = {Advances in Space Research},
publisher = {Elsevier BV},
year = {2015},
volume = {55},
number = {1},
pages = {135--149},
url = {http://dx.doi.org/10.1016/j.asr.2014.10.004 http://linkinghub.elsevier.com/retrieve/pii/S0273117714006322},
doi = {https://doi.org/10.1016/j.asr.2014.10.004}
}

Nguyen, H.n. Apport du GPS pour la quantification des déformations extrêmement lentes et mouvements verticaux dans les chaînes de montagnes fran¸ caises 2015 (2015MONTS246)School: Université Montpellier  phdthesis URL
BibTeX:
@phdthesis{Nguyen2015,
author = {Nguyen, Hai ninh},
title = {Apport du GPS pour la quantification des déformations extrêmement lentes et mouvements verticaux dans les chaînes de montagnes fran¸ caises},
school = {Université Montpellier},
year = {2015},
number = {2015MONTS246},
url = {https://tel.archives-ouvertes.fr/tel-02102910}
}

Nguyen, H.N., Vernant, P., Mazzotti, S., Khazaradze, G. and Asensio, E. 3-D GPS velocity field and its implications on the present-day post-orogenic deformation of the Western Alps and Pyrenees 2016 Solid Earth
Vol. 7(5), pp. 1349-1363
article DOI
Abstract: We present a new 3-D GPS velocity solution for 182 sites for the region encompassing the Western Alps, Pyrenees, and southern France. The velocity field is based on a Precise Point Positioning (PPP) solution, to which we apply a common-mode filter, defined by the 26 longest time series, in order to correct for network-wide biases (reference frame, unmodeled large-scale processes, etc.). We show that processing parameters, such as troposphere delay modeling, can lead to systematic velocity variations of 0.1–0.5 mm yr−1 affecting both accuracy and precision, especially for short (&lt; 5 years) time series. A velocity convergence analysis shows that minimum time-series lengths of ∼ 3 and ∼ 5.5 years are required to reach a velocity stability of 0.5 mm yr−1 in the horizontal and vertical components, respectively. On average, horizontal residual velocities show a stability of ∼ 0.2 mm yr−1 in the Western Alps, Pyrenees, and southern France. The only significant horizontal strain rate signal is in the western Pyrenees with up to 4 × 10−9 yr−1 NNE–SSW extension, whereas no significant strain rates are detected in the Western Alps (&lt; 1 × 10−9 yr−1). In contrast, we identify significant uplift rates up to 2 mm yr−1 in the Western Alps but not in the Pyrenees (0.1 ± 0.2 mm yr−1). A correlation between site elevations and fast uplift rates in the northern part of the Western Alps, in the region of the Würmian ice cap, suggests that part of this uplift is induced by postglacial rebound. The very slow uplift rates in the southern Western Alps and in the Pyrenees could be accounted for by erosion-induced rebound.
BibTeX:
@article{Nguyen2016a,
author = {Nguyen, Hai Ninh and Vernant, Philippe and Mazzotti, Stephane and Khazaradze, Giorgi and Asensio, Eva},
title = {3-D GPS velocity field and its implications on the present-day post-orogenic deformation of the Western Alps and Pyrenees},
journal = {Solid Earth},
year = {2016},
volume = {7},
number = {5},
pages = {1349--1363},
doi = {https://doi.org/10.5194/se-7-1349-2016}
}

Nicolas, J., Durand, S., Vergnolle, M., Morel, L., Melachroinos, S., Bouin, M.N. and Fund, F. Ocean Loading in Brittany, Northwest France: Impact of the GPS Analysis Strategy 2012
Vol. 137International Association of Geodesy Symposia, pp. 367-372
incollection DOI URL
BibTeX:
@incollection{Nicolas2012,
author = {Nicolas, Joëlle and Durand, Stéphane and Vergnolle, Mathilde and Morel, Laurent and Melachroinos, Stavros and Bouin, Marie Noëlle and Fund, François},
title = {Ocean Loading in Brittany, Northwest France: Impact of the GPS Analysis Strategy},
booktitle = {International Association of Geodesy Symposia},
publisher = {Springer Science backslashmathplus Business Media},
year = {2012},
volume = {137},
pages = {367--372},
doi = {https://doi.org/10.1007/978-3-642-22078-4%7B%5C_%7D55}
}

Nicolas, J., Perosanz, F., Rigo, A., Le Bliguet, G., Morel, L. and Fund, F. Impact of loading phenomena on velocity field computation from GPS campaigns: Application to ResPyr GPS campaign in the Pyrenees 2012
Vol. 136International Association of Geodesy Symposia, pp. 643-649
incollection DOI URL
BibTeX:
@incollection{Nicolas2012b,
author = {Nicolas, J. and Perosanz, F. and Rigo, A. and Le Bliguet, G. and Morel, L. and Fund, F.},
title = {Impact of loading phenomena on velocity field computation from GPS campaigns: Application to ResPyr GPS campaign in the Pyrenees},
booktitle = {International Association of Geodesy Symposia},
publisher = {Springer Science backslashmathplus Business Media},
year = {2012},
volume = {136},
pages = {643--649},
doi = {https://doi.org/10.1007/978-3-642-20338-1%7B%5C_%7D79}
}

Nocquet, J.M., Sue, C., Walpersdorf, A., Tran, T., Lenôtre, N., Vernant, P., Cushing, M., Jouanne, F., Masson, F., Baize, S., Chéry, J. and van der Beek, P.A. Present-day uplift of the western Alps 2016 Nature Publishing Group
Vol. 6(June), pp. 1-6
article DOI URL
Abstract: Collisional mountain belts grow as a consequence of continental plate convergence and eventually disappear under the combined effects of gravitational collapse and erosion. Using a decade of GPS data, we show that the western Alps are currently characterized by zero horizontal velocity boundary conditions, offering the opportunity to investigate orogen evolution at the time of cessation of plate convergence. We find no significant horizontal motion within the belt, but GPS and levelling measurements independently show a regional pattern of uplift reaching ˜2.5 mm/yr in the northwestern Alps. Unless a low viscosity crustal root under the northwestern Alps locally enhances the vertical response to surface unloading, the summed effects of isostatic responses to erosion and glaciation explain at most 60% of the observed uplift rates. Rock-uplift rates corrected from transient glacial isostatic adjustment contributions likely exceed erosion rates in the northwestern Alps. In the absence of active convergence, the observed surface uplift must result from deep-seated processes.
BibTeX:
@article{Nocquet2016a,
author = {Nocquet, J M and Sue, C and Walpersdorf, A and Tran, T and Lenôtre, N and Vernant, P and Cushing, M and Jouanne, F and Masson, F and Baize, S and Chéry, J and van der Beek, P A},
title = {Present-day uplift of the western Alps},
journal = {Nature Publishing Group},
publisher = {Nature Publishing Group},
year = {2016},
volume = {6},
number = {June},
pages = {1--6},
url = {http://dx.doi.org/10.1038/srep28404},
doi = {https://doi.org/10.1038/srep28404}
}

de Oliveira, P.S., Morel, L., Fund, F., Legros, R., Monico, J.F., Durand, S. and Durand, F. Modeling tropospheric wet delays with dense and sparse network configurations for PPP-RTK 2017 GPS Solutions
Vol. 21(1), pp. 237-250
article DOI URL
Abstract: Precise Point Positioning (PPP) is a well-known technique of positioning by Global Navigation Satellite Systems (GNSS) that provides accurate solutions. With the availability of real-time precise orbit and clock products provided by the International GNSS Service (IGS) and by individual analysis centers such as Centre National d’Etudes Spatiales through the IGS Real-Time Project, PPP in real time is achievable. With such orbit and clock products and using dual-frequency receivers, first-order ionospheric effects can be eliminated by the ionospheric-free combination. Concerning the tropospheric delays, the Zenith Hydrostatic Delays can be quite well modeled, although the Zenith Wet Delays (ZWDs) have to be estimated because they cannot be mitigated by, for instance, observable combinations. However, adding ZWD estimates in PPP processing increases the time to achieve accurate positions. In order to reduce this convergence time, we (1) model the behavior of troposphere over France using ZWD estimates at Orphéon GNSS reference network stations and (2) send the modeling parameters to the GNSS users to be introduced as a priori ZWDs, with an appropriate uncertainty. At the user level, float PPP-RTK is achieved; that is, GNSS data are performed in kinematic mode and ambiguities are kept float. The quality of the modeling is assessed by comparison with tropospheric products published by Institut National de l’Information Géographique et Forestière. Finally, the improvements in terms of required time to achieve 10-cm accuracy for the rover position (simulated float PPP-RTK) are quantified and discussed. Results for 68 % quantiles of absolute errors convergence show that gains for GPS-only positioning with ZWDs derived from the assessed tropospheric modeling are about: 1 % (East), 20 % (North), and 5 % (Up). Since ZWD estimation is correlated with satellite geometry, we also investigated the positioning when processing GPS + GLONASS data, which increases significantly the number of available satellites. The improvements achieved by adding tropospheric corrections in this case are about: 2 % (East), 5 % (North), and 13 % (Up). Finally, a reduction in the number of reference stations by using a sparser network configuration to perform the tropospheric modeling does not degrade the generated tropospheric corrections, and similar performances are achieved.
BibTeX:
@article{Oliveira2017a,
author = {de Oliveira, P. S. and Morel, L. and Fund, F. and Legros, R. and Monico, J. F.G. and Durand, S. and Durand, F.},
title = {Modeling tropospheric wet delays with dense and sparse network configurations for PPP-RTK},
journal = {GPS Solutions},
year = {2017},
volume = {21},
number = {1},
pages = {237--250},
doi = {https://doi.org/10.1007/s10291-016-0518-0}
}

Ponton, F., Walpersdorf, A., Gay, M., Trouvé, E., Mugnier, J.L., Fallourd, R. and Cotte, N. GPS and TerraSAR-X time series measure temperate glacier flow in the Mont Blanc massif ( France ): the Argentière glacier test site . 2012
Vol. 14EGU General Assembly Conference Abstracts, pp. 9525
inproceedings
BibTeX:
@inproceedings{Ponton2012a,
author = {Ponton, F and Walpersdorf, A and Gay, M and Trouvé, E and Mugnier, J L and Fallourd, R and Cotte, N},
title = {GPS and TerraSAR-X time series measure temperate glacier flow in the Mont Blanc massif ( France ): the Argentière glacier test site .},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2012},
volume = {14},
pages = {9525}
}

Ponton, F., Trouvé, E., Gay, M., Walpersdorf, A., Fallourd, R., Nicolas, J.M., Vernier, F. and Mugnier, J.L. ObServation of the Argentière glacier flow variability from 2009 to 2011 by TerraSAR-X and GPS displacement measurements 2014 IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Vol. 7(8), pp. 3274-3284
article DOI URL
BibTeX:
@article{Ponton2014a,
author = {Ponton, Fanny and Trouvé, Emmanuel and Gay, Michel and Walpersdorf, Andrea and Fallourd, Renaud and Nicolas, Jean Marie and Vernier, Flavien and Mugnier, Jean Louis},
title = {ObServation of the Argentière glacier flow variability from 2009 to 2011 by TerraSAR-X and GPS displacement measurements},
journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
publisher = {Institute of Electrical & Electronics Engineers (IEEE)},
year = {2014},
volume = {7},
number = {8},
pages = {3274--3284},
url = {http://dx.doi.org/10.1109/jstars.2014.2349004},
doi = {https://doi.org/10.1109/JSTARS.2014.2349004}
}

Rabin, M., Sue, C. and Walpersdorf, A. Active deformations of the Jura arc inferred by GPS and seismotectonics 2016
Vol. 18EGU General Assembly Conference Abstracts, pp. 1845
inproceedings
BibTeX:
@inproceedings{Rabin2016a,
author = {Rabin, M and Sue, C and Walpersdorf, A},
title = {Active deformations of the Jura arc inferred by GPS and seismotectonics},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2016},
volume = {18},
pages = {1845}
}

Razak, K.A., Bucksch, A., Damen, M., van Westen, C., Straatsma, M. and de Jong, S. Characterizing Tree Growth Anomaly Induced by Landslides Using LiDAR 2013 Landslide Science and Practice, pp. 235-241  incollection DOI URL
BibTeX:
@incollection{Razak2013a,
author = {Razak, Khamarrul A. and Bucksch, Alexander and Damen, Michiel and van Westen, Cees and Straatsma, Menno and de Jong, Steven},
title = {Characterizing Tree Growth Anomaly Induced by Landslides Using LiDAR},
booktitle = {Landslide Science and Practice},
publisher = {Springer Science backslashmathplus Business Media},
year = {2013},
pages = {235--241},
doi = {https://doi.org/10.1007/978-3-642-31325-7%7B%5C_%7D31}
}

Rigo, A., Vernant, P., Feigl, K.L., Goula, X., Khazaradze, G., Talaya, J., Morel, L., Nicolas, J., Baize, S., Chéry, J. and Sylvander, M. Present-day deformation of the pyrenees revealed by GPS surveying and earthquake focal mechanisms until 2011 2015 Geophysical Journal International
Vol. 201(2), pp. 947-964
article DOI URL
Abstract: The Pyrenean mountain range is a slowly deforming belt with continuous and moderate seismic activity. To quantify its deformation field, we present the velocity field estimated from a GPS survey of the Pyrenees spanning 18 yr. The PotSis and ResPyr networks, including a total of 85 GPS sites, were installed and first measured in 1992 and 1995–1997, respectively, and remeasured in 2008 and 2010. We obtain a deformation field with velocities less than 1 mm yr−1 across the range. The estimated velocities for individual stations do not differ significantly from zero with 95 per cent confidence. Even so, we estimate a maximum extensional horizontal strain rate of 2.0 ± 1.7 nanostrain per year in a N–S direction in the western part of the range. We do not interpret the vertical displacements due to their large uncertainties. In order to compare the horizontal strain rates with the seismic activity, we analyse a set of 194 focal mechanisms using three methods: (i) the ‘r’ factor relating their P and T axes, (ii) the stress tensors obtained by fault slip inversion and (iii) the strain-rate tensors. Stress and strain-rate tensors are estimated for: (i) the whole data set, (ii) the eastern and western parts of the range separately, and (iii) eight zones, which are defined based on the seismicity and the tectonic patterns of the Pyrenees. Each of these analyses reveals a lateral variation of the deformation style from compression and extension in the east to extension and strike-slip in the west of the range. Although the horizontal components of the strain-rate tensors estimated from the seismic data are slightly smaller in magnitude than those computed from the GPS velocity field, they are consistent within the 2σ uncertainties. Furthermore, the orientations of their principal axes agree with the mapped active faults.
BibTeX:
@article{Rigo2015a,
author = {Rigo, A. and Vernant, P. and Feigl, K. L. and Goula, X. and Khazaradze, G. and Talaya, J. and Morel, L. and Nicolas, J. and Baize, S. and Chéry, J. and Sylvander, M.},
title = {Present-day deformation of the pyrenees revealed by GPS surveying and earthquake focal mechanisms until 2011},
journal = {Geophysical Journal International},
publisher = {Oxford University Press (OUP)},
year = {2015},
volume = {201},
number = {2},
pages = {947--964},
url = {http://gji.oxfordjournals.org/content/201/2/947.abstract},
doi = {https://doi.org/10.1093/gji/ggv052}
}

Rudenko, S., Schön, N., Uhlemann, M. and Gendt, G. Reprocessed height time series for GPS stations 2013 Solid Earth
Vol. 4(1), pp. 23-41
article DOI URL
Abstract: Precise weekly positions of 403 Global Positioning System (GPS) stations located worldwide are obtained by reprocessing GPS data of these stations for the time span from 4 January 1998 until 29 December 2007. The processing algorithms and models used as well as the solution and results obtained are presented. Vertical velocities of 266 GPS stations having a tracking history longer than 2.5 yr are computed; 107 of them are GPS stations located at tide gauges (TIGA observing stations). The vertical velocities calculated in this study are compared with the estimates from the co-located tide gauges and other GPS solutions. The formal errors of the estimated vertical velocities are 0.01–0.80 mm yr−1. The vertical velocities of our solution agree within 1 mm yr−1 with those of the recent solutions (ULR5 and ULR3) of the Université de La Rochelle for about 67–75 per cent of the common stations. Examples of typical behaviour of station height changes are given and interpreted. The derived height time series and vertical motions of continuous GPS at tide gauges stations can be used for correcting the vertical land motion in tide gauge records of sea level changes.
BibTeX:
@article{Rudenko2013a,
author = {Rudenko, S. and Schön, N. and Uhlemann, M. and Gendt, G.},
title = {Reprocessed height time series for GPS stations},
journal = {Solid Earth},
publisher = {Copernicus GmbH},
year = {2013},
volume = {4},
number = {1},
pages = {23--41},
url = {http://www.solid-earth.net/4/23/2013/},
doi = {https://doi.org/10.5194/se-4-23-2013}
}

Sakic-Kieffer, P. Apport de la géodésie fond de mer à l’évaluation de l’aléa sismique côtier : distancemétrie en mer de Marmara et simulation de GNSS/A aux Antilles 2016 , pp. 368  phdthesis
BibTeX:
@phdthesis{SakicKieffer2016a,
author = {Sakic-Kieffer, Pierre},
title = {Apport de la géodésie fond de mer à l’évaluation de l’aléa sismique côtier : distancemétrie en mer de Marmara et simulation de GNSS/A aux Antilles},
year = {2016},
pages = {368}
}

Santamar\ia-Gómez, A., Bouin, M.N. and Wöppelmann, G. Improved GPS data analysis strategy for tide gauge benchmark monitoring 2012
Vol. 136International Association of Geodesy Symposia, pp. 11-18
incollection DOI URL
BibTeX:
@incollection{SantamariaGomez2012a,
author = {Santamar\ia-Gómez, Alvaro and Bouin, Marie Noëlle and Wöppelmann, Guy},
title = {Improved GPS data analysis strategy for tide gauge benchmark monitoring},
booktitle = {International Association of Geodesy Symposia},
publisher = {Springer Science Business Media},
year = {2012},
volume = {136},
pages = {11--18},
url = {http://dx.doi.org/10.1007/978-3-642-20338-1_2},
doi = {https://doi.org/10.1007/978-3-642-20338-1%7B%5C_%7D2}
}

Santamar\ia-Gómez, A., Marie-Noëlle, B., Collilieux, X. and Wöppelmann, G. Time-Correlated GPS Noise Dependency on Data Time Period 2013
Vol. 138International Association of Geodesy Symposia, pp. 119-124
incollection DOI URL
BibTeX:
@incollection{SantamariaGomez2013a,
author = {Santamar\ia-Gómez, Alvaro and Marie-Noëlle, Bouin and Collilieux, Xavier and Wöppelmann, Guy},
title = {Time-Correlated GPS Noise Dependency on Data Time Period},
booktitle = {International Association of Geodesy Symposia},
publisher = {Springer Science backslashmathplus Business Media},
year = {2013},
volume = {138},
pages = {119--124},
doi = {https://doi.org/10.1007/978-3-642-32998-2%7B%5C_%7D19}
}

Santamar\ia-Gómez, A., Watson, C., Gravelle, M., King, M. and Wöppelmann, G. Levelling co-located GNSS and tide gauge stations using GNSS reflectometry 2015 Journal of Geodesy
Vol. 89(3), pp. 241-258
article DOI URL
Abstract: The GNSS reflectometry technique provides geometric information on the environment surrounding the GNSS antenna including the vertical distance to a reflecting surface. We use sea-surface reflections of GPS signals, recorded as oscillations in signal-to-noise ratio (SNR), to estimate the GNSS to tide gauge (TG) levelling tie, and thus the ellipsoidal heights of the TG. We develop approaches to isolate SNR data dominated by sea-surface reflections and to remove SNR frequency changes caused by the dynamic sea surface. Comparison with in situ levelling at eight sites reveals mean differences at the centimetre level for satellites above 12 backslash(ˆbackslashcirc backslash) elevation, with four sites showing differences of 3 cm or smaller. These differences include errors in the in situ levelling, in the antenna calibration model and in the TG measurements, and so represent an upper bound on our technique’s error. Data sampling (1 or 30 s) does not significantly affect the results. We detect systematic errors at the decimetre level related to satellite elevations below 12 backslash(ˆbackslashcirc backslash) and to sea-surface height and also differences between results from the L1 and L2 GPS signals larger than 15 cm at two sites. These systematic errors remain unexplained; differences between GPS signals are attributed to receiver-dependent differences in the SNR measurements, while the elevation-dependent error is attributed to unmodelled phase effects such as those caused by tropospheric refraction and sea-surface roughness. Using our approach, we identify a levelling offset of 1.5 cm related to a TG sensor change, illustrating our technique’s value for TG reference monitoring.
BibTeX:
@article{SantamariaGomez2015a,
author = {Santamar\ia-Gómez, Alvaro and Watson, Christopher and Gravelle, Médéric and King, Matt and Wöppelmann, Guy},
title = {Levelling co-located GNSS and tide gauge stations using GNSS reflectometry},
journal = {Journal of Geodesy},
publisher = {Springer Science Business Media},
year = {2015},
volume = {89},
number = {3},
pages = {241--258},
url = {http://dx.doi.org/10.1007/s00190-014-0784-y},
doi = {https://doi.org/10.1007/s00190-014-0784-y}
}

Sguerso, D., Labbouz, L. and Walpersdorf, A. 14 years of GPS tropospheric delays in the French–Italian border region: comparisons and first application in a case study 2016 Applied Geomatics
Vol. 8(1), pp. 13-25
article DOI URL
Abstract: Global Positioning System (GPS) data from 181 permanent stations extracted from different networks covering France and the Italian part of the Alps are used to estimate a homogeneous set of tropospheric parameters over 14 years (from January 1998 to May 2012). The tropospheric Zenith Total Delay (ZTD) quantified in the GPS data analysis is closely related to the value of integrated water vapor above each GPS station. GPS ZTD is already successfully used for operational weather prediction and meteorological analyses, providing valuable data to improve our comprehension of the tropospheric water cycle and in particular to improve the prediction of precipitations. Moreover, GPS tropospheric measurements are intrinsically stable, so that long-term observations represent a significant contribution to climatological studies. The results of a homogeneous reanalysis of up to 14 years of data with MIT’s GAMIT/GLOBK software are presented. The estimated tropospheric parameters are one ZTD every 2 h and one couple of horizontal tropospheric gradients, seven times a day for each station, simultaneously with a daily positioning solution. A quality check of the tropospheric parameter time series identifies offsets, for example, due to instrument changes at individual sites. Our analysis strategy using the empirical GMF is validated by a comparison with the new GPT2 model. Moreover, a comparison with the IGS analysis of 1 year is provided for common stations. The resulting verified time series can be used for meteorological and climatological studies. As first examples, we present a convergence test for the ZTD change in time and a regional climatological approach that could permit identifying specific patterns of ZTD variation that are related to severe weather events. The 181 ZTD and gradient time series are made available in the Reseau National GPS permanent (RENAG) database.
BibTeX:
@article{Sguerso2016a,
author = {Sguerso, Domenico and Labbouz, Laurent and Walpersdorf, Andrea},
title = {14 years of GPS tropospheric delays in the French–Italian border region: comparisons and first application in a case study},
journal = {Applied Geomatics},
publisher = {Springer Science backslashmathplus Business Media},
year = {2016},
volume = {8},
number = {1},
pages = {13--25},
doi = {https://doi.org/10.1007/s12518-015-0158-z}
}

Sneeuw, N., Novák, P., Crespi, M. and Sansó, F. VII Hotine-Marussi Symposium on Mathematical Geodesy: Proceedings of the Symposium in Rome, 6-10 June, 2009 2012
Vol. 137International Association of Geodesy Symposia, pp. 39-45
book DOI URL
BibTeX:
@book{Sneeuw2012a,
author = {Sneeuw, Nico and Novák, Pavel and Crespi, Mattia and Sansó, Fernando},
title = {VII Hotine-Marussi Symposium on Mathematical Geodesy: Proceedings of the Symposium in Rome, 6-10 June, 2009},
booktitle = {International Association of Geodesy Symposia},
publisher = {Springer Berlin Heidelberg},
year = {2012},
volume = {137},
pages = {39--45},
doi = {https://doi.org/10.1007/978-3-642-22078-4}
}

Socquet, A., Déprez, A., Cotte, N., Maubant, L., Walpersdorf, A. and Bato, M.G. Present-day deformation in Europe, as seen by the EPOS-GNSS prototype solution in double difference, and first co-and post-seismic displacements associated with 2016 Amatrice and Norcia earthquakes (Italy) 2017
Vol. 19EGU General Assembly Conference Abstracts, pp. 17467
inproceedings
BibTeX:
@inproceedings{Socquet2017a,
author = {Socquet, Anne and Déprez, Aline and Cotte, Nathalie and Maubant, Louise and Walpersdorf, Andrea and Bato, Mary Grace},
title = {Present-day deformation in Europe, as seen by the EPOS-GNSS prototype solution in double difference, and first co-and post-seismic displacements associated with 2016 Amatrice and Norcia earthquakes (Italy)},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2017},
volume = {19},
pages = {17467}
}

Tornatore, V., Tanır Kayıkçı, E. and Roggero, M. Comparison of ITRF2014 station coordinate input time series of DORIS, VLBI and GNSS 2016 Advances in Space Research
Vol. 58(12), pp. 2742-2757
article DOI URL
Abstract: In this paper station coordinate time series from three space geodesy techniques that have contributed to the realization of the International Terrestrial Reference Frame 2014 (ITRF2014) are compared. In particular the height component time series extracted from official combined intra-technique solutions submitted for ITRF2014 by DORIS, VLBI and GNSS Combination Centers have been investigated. The main goal of this study is to assess the level of agreement among these three space geodetic techniques. A novel analytic method, modeling time series as discrete-time Markov processes, is presented and applied to the compared time series. The analysis method has proven to be particularly suited to obtain quasi-cyclostationary residuals which are an important property to carry out a reliable harmonic analysis. We looked for common signatures among the three techniques. Frequencies and amplitudes of the detected signals have been reported along with their percentage of incidence. Our comparison shows that two of the estimated signals, having one-year and 14 days periods, are common to all the techniques. Different hypotheses on the nature of the signal having a period of 14 days are presented. As a final check we have compared the estimated velocities and their standard deviations (STD) for the sites that co-located the VLBI, GNSS and DORIS stations, obtaining a good agreement among the three techniques both in the horizontal (1.0 mm/yr mean STD) and in the vertical (0.7 mm/yr mean STD) component, although some sites show larger STDs, mainly due to lack of data, different data spans or noisy observations.
BibTeX:
@article{Tornatore2016a,
author = {Tornatore, Vincenza and Tanır Kayıkçı, Emine and Roggero, Marco},
title = {Comparison of ITRF2014 station coordinate input time series of DORIS, VLBI and GNSS},
journal = {Advances in Space Research},
year = {2016},
volume = {58},
number = {12},
pages = {2742--2757},
url = {//www.sciencedirect.com/science/article/pii/S0273117716303751},
doi = {https://doi.org/10.1016/j.asr.2016.07.016}
}

Tran, D.T. Analyse rapide et robuste des solutions GPS pour la tectonique 2013 (2013NICE4033)School: Université Nice Sophia Antipolis  phdthesis URL
BibTeX:
@phdthesis{Tran2013,
author = {Tran, Dinh Trong},
title = {Analyse rapide et robuste des solutions GPS pour la tectonique},
school = {Université Nice Sophia Antipolis},
year = {2013},
number = {2013NICE4033},
url = {https://tel.archives-ouvertes.fr/tel-00868030}
}

Tu, R., Zhang, H., Ge, M. and Huang, G. A real-time ionospheric model based on GNSS Precise Point Positioning 2013 Advances in Space Research
Vol. 52(6), pp. 1125-1134
article DOI URL
Abstract: This paper proposes a method of real-time monitoring and modeling the ionospheric Total Electron Content (TEC) by Precise Point Positioning (PPP). Firstly, the ionospheric TEC and receiver's Differential Code Biases (DCB) are estimated with the undifferenced raw observation in real-time, then the ionospheric TEC model is established based on the Single Layer Model (SLM) assumption and the recovered ionospheric TEC. In this study, phase observations with high precision are directly used instead of phase smoothed code observations. In addition, the DCB estimation is separated from the establishment of the ionospheric model which will limit the impacts of the SLM assumption impacts. The ionospheric model is established at every epoch for real time application. The method is validated with three different GNSS networks on a local, regional, and global basis. The results show that the method is feasible and effective, the real-time ionosphere and DCB results are very consistent with the IGS final products, with a bias of 1-2 TECU and 0.4 ns respectively. ?? 2013 COSPAR. The Authors. Published by Elsevier Ltd. All rights reserved.
BibTeX:
@article{Tu2013a,
author = {Tu, Rui and Zhang, Hongping and Ge, Maorong and Huang, Guanwen},
title = {A real-time ionospheric model based on GNSS Precise Point Positioning},
journal = {Advances in Space Research},
publisher = {Elsevier BV},
year = {2013},
volume = {52},
number = {6},
pages = {1125--1134},
url = {http://dx.doi.org/10.1016/j.asr.2013.06.015},
doi = {https://doi.org/10.1016/j.asr.2013.06.015}
}

Van Baelen, J. and Penide, G. Study of water vapor vertical variability and possible cloud formation with a small network of GPS stations 2009 Geophysical Research Letters
Vol. 36(2), pp. n/a--n/a
article DOI URL
Abstract: During a short experiment we have investigated the vertical variability of water vapor in the lower part of the atmosphere with the help of small network of GPS stations positioned on the eastern slopes of the Puy de DÃ´me in central France. We have found out that the urban layer exhibits somewhat constant water vapor content. In contrast, the major IWV variations arise in the upper troposphere level, in particular in the presence of westerly flows that bring elevated water vapor content over the mountain ridge. Finally, the transition layer situated between these lower and upper levels presents quite variable water vapor content, acting as a buffer zone for the boundary layer. Comparing two episodes of higher water vapor contents, one being associated with a sharp frontal passage, we have shown that the contrasted behavior of the different layers revealed the possible formation of clouds before the advent of rain.
BibTeX:
@article{VanBaelen2009a,
author = {Van Baelen, Joël and Penide, Guillaume},
title = {Study of water vapor vertical variability and possible cloud formation with a small network of GPS stations},
journal = {Geophysical Research Letters},
publisher = {Wiley-Blackwell},
year = {2009},
volume = {36},
number = {2},
pages = {n/a----n/a},
url = {http://dx.doi.org/10.1029/2008gl036148},
doi = {https://doi.org/10.1029/2008GL036148}
}

Van Baelen, J., Reverdy, M., Tridon, F., Labbouz, L., Dick, G., Bender, M. and Hagen, M. On the relationship between water vapour field evolution and the life cycle of precipitation systems 2011 Quarterly Journal of the Royal Meteorological Society
Vol. 137(SUPPL. 1), pp. 204-223
article DOI URL
Abstract: In this work, we investigate the relationship between the structure and evolution (from initiation to decay) of precipitation systems, and the associated water vapour distributions during the COPS (Convective Orographically-induced Precipitation Study). This international field campaign took place over an area from the Vosges to the Black Forest Mountains, across the Rhine Valley, in summer 2007. In particular, we consider water vapour retrieval through GPS integrated water vapour 2D maps and 3D tomography, and compare these to precipitation systems observed with the ground-based C-band POLDIRAD weather radar. We have demonstrated the predominant role of water vapour as a precursor to convective initiation for local convective cell generation. Water vapour accumulation on the crest of the orography is associated with ridge convection, while water vapour passing over the mountain top and creating valley outflows generates lee-side convection, often triggered by a small hill positioned within or close to the valley exit, or by a local convergence with the water vapour field over the plain. We have also noted that frontal systems seem to develop preferentially where the largest amount of water vapour is available. Likewise, in the case of frontal systems, well-formed synoptic-scale storms are associated with high water vapour signatures, while weaker systems with embedded convection appear to trail high water vapour areas where the convective element is associated with local water vapour depletion. This latter aspect could be the signature of convective cloud formation, when water vapour is transferred into liquid water, before the onset of precipitation. Copyright © 2011 Royal Meteorological Society
BibTeX:
@article{VanBaelen2011a,
author = {Van Baelen, J. and Reverdy, M. and Tridon, F. and Labbouz, L. and Dick, G. and Bender, M. and Hagen, M.},
title = {On the relationship between water vapour field evolution and the life cycle of precipitation systems},
journal = {Quarterly Journal of the Royal Meteorological Society},
publisher = {Wiley-Blackwell},
year = {2011},
volume = {137},
number = {SUPPL. 1},
pages = {204--223},
url = {http://dx.doi.org/10.1002/qj.785},
doi = {https://doi.org/10.1002/qj.785}
}

Van Vliet-Lanoë, B., Penaud, A., Hénaff, A., Delacourt, C., Fernane, A., Goslin, J., Hallégouët, B. and Le Cornec, E. Middle- to late-Holocene storminess in Brittany (NW France): Part II – The chronology of events and climate forcing 2014 The Holocene
Vol. 24(4), pp. 434-453
article DOI URL
Abstract: This study focuses on the recurring climate conditions required for the largest storms occurring in NW France (Brittany). It is based on the analysed records of storm events along Western Brittany coast (see Part I). In this manuscript (Part II), storm recurrence is explored along with forcing mechanisms. Periods of more frequent storm events over the two last centuries are analysed first in order to link these events with possible forcing mechanisms (North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO) modes) triggering the most destructive storms. Then, palaeostorm events are discussed at the Holocene scale, from 6000 yr BP to present, to verify the forcing mechanisms. Most recorded events appear to be linked with cooling episodes, mostly in winter, a transition to or from a negative winter NAO mode, a positive AMO mode. Extreme storms occur immediately prior to the ‘Medieval Warm Period’ (MWP). Maximum effects are reached prior to the onset of the MWP and during the Maunder and Dalton solar minima. Low storm activity occurred during the Spörer Minimum linked to an acceleration of the Atlantic Meridional Overturning Circulation (AMOC). Main storm triggers seem to correspond to a positive AMO mode with an unstable jetstream configuration driving a negative NAO. In this study, four specific weather configurations were defined to explain each type of recorded storminess. The strongest storms correspond to low AMO and decennial-negative NAO modes (e.g. ‘Little Ice Age’), or high AMO in association with dominant low NAO modes, as during the early Middle Age and present-day period. Fresh or warm oceans in association with a positive NAO mode are stormy but with very low sting storms frequency. Although in agreement with the orbital forcing and the Holocene glacial history, increasing storm frequency and intensity is most probably partly biased by continuous sea-level rise and resulting erosion.
BibTeX:
@article{VanVlietLanoe2014a,
author = {Van Vliet-Lanoë, Brigitte and Penaud, Aurélie and Hénaff, Alain and Delacourt, Christophe and Fernane, Assia and Goslin, Jérôme and Hallégouët, Bernard and Le Cornec, Erwan},
title = {Middle- to late-Holocene storminess in Brittany (NW France): Part II – The chronology of events and climate forcing},
journal = {The Holocene},
publisher = {SAGE Publications},
year = {2014},
volume = {24},
number = {4},
pages = {434--453},
url = {http://hol.sagepub.com/content/24/4/434.abstract},
doi = {https://doi.org/10.1177/0959683613519688}
}

Vey, S., Dietrich, R., Fritsche, M., Rülke, A., Steigenberger, P. and Rothacher, M. On the homogeneity and interpretation of precipitable water time series derived from global GPS observations 2009 Journal of Geophysical Research Atmospheres
Vol. 114(10)
article DOI URL
Abstract: Observations of the Global Positioning System (GPS) were reanalyzedbackslashnover the period from 1994 to 2004 in a joint project of the technicalbackslashnuniversities in Dresden and Munich. The estimated tropospheric parametersbackslashnwere converted into precipitable water (PW) using surface pressurebackslashnobservations from the World Meteorological Organization and atmosphericbackslashnmean temperature fields from the European Centre for Medium-RangebackslashnWeather Forecasts. For the first time a systematic study of the homogeneitybackslashnof global GPS-derived precipitable water time series was carriedbackslashnout regarding the influence of changes in the GPS antennas and radomesbackslashnas well as changes in the number of recorded observations. The focusbackslashnof this study is on interannual changes in precipitable water. OverbackslashnEurope, large parts of North America, and Iceland and in the regionbackslashnsouth of 30°S, these changes are very small. The range of the PWbackslashnvariations on interannual time scales is less than 2 mm in thesebackslashnareas. However, in the southeastern part of North America and northbackslashnAustralia, these anomalies in precipitable water show a range ofbackslashnup to 6 mm. In the tropics, PW anomalies with a range of up to 10backslashnmm were found. GPS PW was compared with a modeled PW assuming waterbackslashnvapor saturation. This shows that GPS PW of stations located in thebackslashnmiddle and high northern and southern latitudes is consistent withbackslashnthe temperature-related saturation values of water vapor. In thebackslashntropics and subtropics the annual temperature variations are low.backslashnIn these regions the variations in the PW can be dominated by otherbackslashnfactors, including water vapor transport. At seasonal time scalesbackslashnthe water vapor transport can be associated with atmospheric circulationbackslashnsuch as monsoonal flow.
BibTeX:
@article{Vey2009a,
author = {Vey, S. and Dietrich, R. and Fritsche, M. and Rülke, A. and Steigenberger, Peter and Rothacher, Markus},
title = {On the homogeneity and interpretation of precipitable water time series derived from global GPS observations},
journal = {Journal of Geophysical Research Atmospheres},
publisher = {Wiley-Blackwell},
year = {2009},
volume = {114},
number = {10},
url = {http://dx.doi.org/10.1029/2008jd010415},
doi = {https://doi.org/10.1029/2008JD010415}
}

Vigny, C., Geiger, A., Calais, E., Chery, J., Feigl, K., Jouanne, F., Walpersdorf, A., Exertier, P., Ferhat, G., Nocquet, J., Briole, P., Charade, O., Delacourt, C., Duquenne, F., Bouin, M., Flouzat, M., Morel, L., Morin, D., Baize, S. and Anzidei, M. Western Alps Crustal Deformation Monitored by Repeated GPS Surveys 2005 AGU Fall Meeting Abstracts  article
BibTeX:
@article{Vigny2005a,
author = {Vigny, C and Geiger, A and Calais, E and Chery, J and Feigl, K and Jouanne, F and Walpersdorf, A and Exertier, P and Ferhat, G and Nocquet, J and Briole, P and Charade, O and Delacourt, C and Duquenne, F and Bouin, M and Flouzat, M and Morel, L and Morin, D and Baize, S and Anzidei, M},
title = {Western Alps Crustal Deformation Monitored by Repeated GPS Surveys},
journal = {AGU Fall Meeting Abstracts},
year = {2005}
}

Viti, M., Mantovani, E., Babbucci, D. and Tamburelli, C. Plate kinematics and geodynamics in the Central Mediterranean 2011 Journal of Geodynamics
Vol. 51(2-3), pp. 190-204
article DOI URL
Abstract: We argue that seismotectonic activity in the Central Mediterranean area and the Aegean-Balkan zone is driven by the NNE-ward motion of Africa and westward motion of Anatolia with respect to Eurasia. These boundary conditions can plausibly and coherently account for E-W shortening and roughly S-N extension in the Aegean domain, thrusting and uplift at the boundary between the Aegean-Balkan system and the Adriatic/Ionian domain (Hellenic trench, Cephalonia fault, Epirus, Albanides and Southern Dinarides), the kinematics of the Adria plate (a large block encompassing the Adriatic continental domain, the northern Ionian zone and Hyblean-Adventure block) and consequently, the complex pattern of deformation recognized at its boundaries. Furthermore, the fact that in our scheme Adria moves almost in connection with Africa is consistent with the lack of an active decoupling zone between Adria and Africa, an evidence that can hardly be reconciled with the kinematics so far proposed for these two plates. The reasons why we adopt an Africa-Eurasia relative motion different from that implied by the popular NUVEL-1 global solution are discussed in detail. Finally, we make some considerations about the possible implications of the presently available geodetic data on the long-term plate kinematics. © 2010 Elsevier Ltd.
BibTeX:
@article{Viti2011a,
author = {Viti, M. and Mantovani, E. and Babbucci, D. and Tamburelli, C.},
title = {Plate kinematics and geodynamics in the Central Mediterranean},
journal = {Journal of Geodynamics},
publisher = {Elsevier BV},
year = {2011},
volume = {51},
number = {2-3},
pages = {190--204},
url = {http://dx.doi.org/10.1016/j.jog.2010.02.006},
doi = {https://doi.org/10.1016/j.jog.2010.02.006}
}

Walpersdorf, A., Brenot, H., Champollion, C., Doerflinger, E., Masson, F., Ducrocq, V., Anquetin, S. and Tabary, P. GPS project for tropospheric water vapour observations related to torrential rain in the French Cevennes: Description and first results of the field experiment. 2003 EGS - AGU - EUG Joint Assembly  inproceedings
BibTeX:
@inproceedings{Walpersdorf2003a,
author = {Walpersdorf, A and Brenot, H and Champollion, C and Doerflinger, E and Masson, F and Ducrocq, V and Anquetin, S and Tabary, P},
title = {GPS project for tropospheric water vapour observations related to torrential rain in the French Cevennes: Description and first results of the field experiment.},
booktitle = {EGS - AGU - EUG Joint Assembly},
year = {2003}
}

Walpersdorf, A., Bock, O., Doerflinger, E., Masson, F., van Baelen, J., Somieski, A. and Bürki, B. Data analysis of a dense GPS network operated during the ESCOMPTE campaign: First results 2004
Vol. 29(2-3)Physics and Chemistry of the Earth, pp. 201-211
inproceedings DOI
BibTeX:
@inproceedings{Walpersdorf2004a,
author = {Walpersdorf, A. and Bock, O. and Doerflinger, E. and Masson, F. and van Baelen, J. and Somieski, A. and Bürki, B.},
title = {Data analysis of a dense GPS network operated during the ESCOMPTE campaign: First results},
booktitle = {Physics and Chemistry of the Earth},
year = {2004},
volume = {29},
number = {2-3},
pages = {201--211},
doi = {https://doi.org/10.1016/j.pce.2004.01.002}
}

Walpersdorf, A., Baize, S., Calais, E., Tregoning, P. and Nocquet, J.M. Deformation in the Jura Mountains (France): First results from semi-permanent GPS measurements 2006 Earth and Planetary Science Letters
Vol. 245(1-2), pp. 365-372
article DOI URL
Abstract: New GPS estimates of relative motion across the Jura Mountain Belt with respect to the Eurasian Plate indicate less than 1 mm/yr of convergence, considerably less than previous estimates. Velocity uncertainties have been evaluated by several methods and range from 0.2 to 0.5 mm/yr for the semi-permanent stations. The major, statistically-significant strain feature inferred by the Jura GPS measurements is along-arc extension, compatible with tectonic studies. That the detected deformation is small in magnitude highlights two important issues: previous estimates are over-stated and that the approach of using semi-permanent GPS installations is capable of detecting small tectonic signals. Using the upper bound as the rate of convergence, we estimate that this would generate an earthquake of magnitude 5-5.5 every 15 to 75 yr. © 2006 Elsevier B.V. All rights reserved.
BibTeX:
@article{Walpersdorf2006a,
author = {Walpersdorf, Andrea and Baize, Stéphane and Calais, Eric and Tregoning, Paul and Nocquet, Jean Mathieu},
title = {Deformation in the Jura Mountains (France): First results from semi-permanent GPS measurements},
journal = {Earth and Planetary Science Letters},
publisher = {Elsevier BV},
year = {2006},
volume = {245},
number = {1-2},
pages = {365--372},
url = {http://dx.doi.org/10.1016/j.epsl.2006.02.037},
doi = {https://doi.org/10.1016/j.epsl.2006.02.037}
}

Walpersdorf, A., Manighetti, I., Mousavi, Z., Tavakoli, F., Vergnolle, M., Jadidi, A., Hatzfeld, D., Aghamohammadi, A., Bigot, A., Djamour, Y., Nankali, H. and Sedighi, M. Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data 2014 Journal of Geophysical Research: Solid Earth
Vol. 119(2), pp. 1359-1383
article DOI
Abstract: We analyze new GPS data spanning 11 years at 92 stations in eastern Iran. We use these data to analyze the present-day kinematics and the slip rates on most seismogenic faults in eastern Iran. The east Lut, west Lut, Kuhbanan, Anar, Dehshir, and Doruneh faults are confirmed as the major faults and are found to currently slip laterally at 5.6 ± 0.6, 4.4 ± 0.4, 3.6 ± 1.3, 2.0 ± 0.7, 1.4 ± 0.9, and 1.3 ± 0.8 mm/yr, respectively. Slip is right-lateral on the ˜NS striking east Lut, west Lut, Kuhbanan, Anar, and Dehshir faults and left-lateral on the ˜EW Doruneh fault. The ˜NS faults slice the eastern Iranian crust into five blocks that are moving northward at 6–13 mm/yr with respect to the stable Afghan crust at the eastern edge of the collision zone. The collective behavior of the ˜NS faults might thus allow the Arabian promontory to impinge northward into the Eurasian crust. The ˜NS faults achieve additional NS shortening by rotating counterclockwise in the horizontal plane, at current rates up to 0.8°/Ma. Modeling the GPS and available geological data with a block rotation model suggests that the rotations have been going on at a similar rate (1 ± 0.4°/Ma) over the last 12 Ma. We identify large strains at the tips of the rotating east Lut, west Lut, and Kuhbanan faults, which we suspect to be responsible for the important historical and instrumental seismicity in those zones.
BibTeX:
@article{Walpersdorf2014a,
author = {Walpersdorf, A. and Manighetti, I. and Mousavi, Z. and Tavakoli, F. and Vergnolle, M. and Jadidi, A. and Hatzfeld, D. and Aghamohammadi, A. and Bigot, A. and Djamour, Y. and Nankali, H. and Sedighi, M.},
title = {Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data},
journal = {Journal of Geophysical Research: Solid Earth},
year = {2014},
volume = {119},
number = {2},
pages = {1359--1383},
doi = {https://doi.org/10.1002/2013JB010620}
}

Walpersdorf, A., Pinget, L., Vernant, P., Sue, C. and Déprez, A. Deformation pattern of the Western Alps from two decades of campaign and permanent GNSS measurements 2017
Vol. 19(1)EGU General Assembly Conference Abstracts, pp. 3046
inproceedings
BibTeX:
@inproceedings{Walpersdorf2017a,
author = {Walpersdorf, A and Pinget, L and Vernant, P and Sue, C and Déprez, A},
title = {Deformation pattern of the Western Alps from two decades of campaign and permanent GNSS measurements},
booktitle = {EGU General Assembly Conference Abstracts},
year = {2017},
volume = {19},
number = {1},
pages = {3046}
}

Wöppelmann, G., Marcos, M., Coulomb, A., Mart\in M\iguez, B., Bonnetain, P., Boucher, C., Gravelle, M., Simon, B. and Tiphaneau, P. Rescue of the historical sea level record of Marseille (France) from 1885 to 1988 and its extension back to 1849-1851 2014 Journal of Geodesy
Vol. 88(9), pp. 869-885
article DOI URL
Abstract: This paper describes the historical sea level data that we have rescued from a tide gauge, especially devised originally for geodesy. This gauge was installed in Marseille in 1884 with the primary objective of defining the origin of the height system in France. Hourly values for 1885-1988 have been digitized from the original tidal charts. They are supplemented by hourly values from an older tide gauge record (1849-1851) that was rediscovered during a survey in 2009. Both recovered data sets have been critically edited for errors and their reliability assessed. The hourly values are thoroughly analysed for the first time after their original recording. A consistent high-frequency time series is reported, increasing notably the length of one of the few European sea level records in the Mediterranean Sea spanning more than one hundred years. Changes in sea levels are examined, and previous results revisited with the extended time series. The rate of relative sea level change for the period 1849-2012 is estimated to have been (Formula presented.) mm/year at Marseille, a value that is slightly lower but in close agreement with the longest time series of Brest over the common period ((Formula presented.) mm/year). The data from a permanent global positioning system station installed on the roof of the solid tide gauge building suggests a remarkable stability of the ground ((Formula presented.) mm/year) since 1998, confirming the choice made by our predecessor geodesists in the nineteenth century regarding this site selection. © 2014 The Author(s).
BibTeX:
@article{Woeppelmann2014a,
author = {Wöppelmann, G. and Marcos, M. and Coulomb, A. and Mart\in M\iguez, B. and Bonnetain, P. and Boucher, C. and Gravelle, M. and Simon, B. and Tiphaneau, P.},
title = {Rescue of the historical sea level record of Marseille (France) from 1885 to 1988 and its extension back to 1849-1851},
journal = {Journal of Geodesy},
publisher = {Springer Science backslashmathplus Business Media},
year = {2014},
volume = {88},
number = {9},
pages = {869--885},
url = {http://dx.doi.org/10.1007/s00190-014-0728-6 http://link.springer.com/10.1007/s00190-014-0728-6},
doi = {https://doi.org/10.1007/s00190-014-0728-6}
}

Woodworth, P.L., Gravelle, M., Marcos, M., Wöppelmann, G. and Hughes, C.W. The status of measurement of the Mediterranean mean dynamic topography by geodetic techniques 2015 Journal of Geodesy
Vol. 89(8), pp. 811-827
article DOI URL
Abstract: © 2015, Springer-Verlag Berlin Heidelberg.We review the measurement of the mean dynamic topography (MDT) of the Mediterranean using ellipsoidal heights of sea level at discrete tide gauge locations, and across the entire basin using satellite altimetry, subtracting estimates of the geoid obtained from recent models. This ‘geodetic approach’ to the determination of the MDT can be compared to the independent ‘ocean approach’ that involves the use of in situ oceanographic measurements and ocean modelling. We demonstrate that with modern geoid and ocean models there is an encouraging level of consistency between the two sets of MDTs. In addition, we show how important geodetic MDT information can be in judging between existing global ocean circulation models, and in providing insight for the development of new ones. The review makes clear the major limitations in Mediterranean data sets that prevent a more complete validation, including the need for improved geoid models of high spatial resolution and accuracy. Suggestions are made on how a greater amount of reliable geo-located tide gauge information can be obtained in the future.
BibTeX:
@article{Woodworth2015a,
author = {Woodworth, Philip L. and Gravelle, Médéric and Marcos, Marta and Wöppelmann, Guy and Hughes, Chris W.},
title = {The status of measurement of the Mediterranean mean dynamic topography by geodetic techniques},
journal = {Journal of Geodesy},
publisher = {Springer Science backslashmathplus Business Media},
year = {2015},
volume = {89},
number = {8},
pages = {811--827},
url = {http://dx.doi.org/10.1007/s00190-015-0817-1},
doi = {https://doi.org/10.1007/s00190-015-0817-1}
}

Wulfmeyer, V., Behrendt, A., Kottmeier, C., Corsmeier, U., Barthlott, C., Craig, G.C., Hagen, M., Althausen, D., Aoshima, F., Arpagaus, M., Bauer, H.S., Bennett, L., Blyth, A., Brandau, C., Champollion, C., Crewell, S., Dick, G., Di Girolamo, P., Dorninger, M., Dufournet, Y., Eigenmann, R., Engelmann, R., Flamant, C., Foken, T., Gorgas, T., Grzeschik, M., Handwerker, J., Hauck, C., Höller, H., Junkermann, W., Kalthoff, N., Kiemle, C., Klink, S., König, M., Krauss, L., Long, C.N., Madonna, F., Mobbs, S., Neininger, B., Pal, S., Peters, G., Pigeon, G., Richard, E., Rotach, M.W., Russchenberg, H., Schwitalla, T., Smith, V., Steinacker, R., Trentmann, J., Turner, D.D., Van Baelen, J., Vogt, S., Volkert, H., Weckwerth, T., Wernli, H., Wieser, A. and Wirth, M. The Convective and Orographically-induced Precipitation Study (COPS): The scientific strategy, the field phase, and research highlights 2011 Quarterly Journal of the Royal Meteorological Society
Vol. 137(SUPPL. 1), pp. 3-30
article DOI URL
Abstract: Within the framework of the international field campaign COPS (Convective and Orographically-induced Precipitation Study), a large suite of state-of-the-art meteorological instrumentation was operated, partially combined for the first time. This includes networks of in situ and remote-sensing systems such as the Global Positioning System as well as a synergy of multi-wavelength passive and active remote-sensing instruments such as advanced radar and lidar systems. The COPS field phase was performed from 01 June to 31 August 2007 in a low-mountain area in southwestern Germany/eastern France covering the Vosges mountains, the Rhine valley and the Black Forest mountains. The collected data set covers the entire evolution of convective precipitation events in complex terrain from their initiation, to their development and mature phase until their decay. Eighteen Intensive Observation Periods with 37 operation days and eight additional Special Observation Periods were performed, providing a comprehensive data set covering different forcing conditions. In this article, an overview of the COPS scientific strategy, the field phase, and its first accomplishments is given. Highlights of the campaign are illustrated with several measurement examples. It is demonstrated that COPS research provides new insight into key processes leading to convection initiation and to the modification of precipitation by orography, in the improvement of quantitative precipitation forecasting by the assimilation of new observations, and in the performance of ensembles of convection-permitting models in complex terrain. Copyright © 2010 Royal Meteorological Society
BibTeX:
@article{Wulfmeyer2011a,
author = {Wulfmeyer, Volker and Behrendt, Andreas and Kottmeier, Christoph and Corsmeier, Ulrich and Barthlott, Christian and Craig, George C. and Hagen, Martin and Althausen, Dietrich and Aoshima, Fumiko and Arpagaus, Marco and Bauer, Hans Stefan and Bennett, Lindsay and Blyth, Alan and Brandau, Christine and Champollion, Cédric and Crewell, Susanne and Dick, Galina and Di Girolamo, Paolo and Dorninger, Manfred and Dufournet, Yann and Eigenmann, Rafael and Engelmann, Ronny and Flamant, Cyrille and Foken, Thomas and Gorgas, Theresa and Grzeschik, Matthias and Handwerker, Jan and Hauck, Christian and Höller, Hartmut and Junkermann, Wolfgang and Kalthoff, Norbert and Kiemle, Christoph and Klink, Stefan and König, Marianne and Krauss, Liane and Long, Charles N. and Madonna, Fabio and Mobbs, Stephen and Neininger, Bruno and Pal, Sandip and Peters, Gerhard and Pigeon, Grégoire and Richard, Evelyne and Rotach, Mathias W. and Russchenberg, Herman and Schwitalla, Thomas and Smith, Victoria and Steinacker, Reinhold and Trentmann, Jörg and Turner, David D. and Van Baelen, Joel and Vogt, Siegfried and Volkert, Hans and Weckwerth, Tammy and Wernli, Heini and Wieser, Andreas and Wirth, Martin},
title = {The Convective and Orographically-induced Precipitation Study (COPS): The scientific strategy, the field phase, and research highlights},
journal = {Quarterly Journal of the Royal Meteorological Society},
publisher = {Wiley-Blackwell},
year = {2011},
volume = {137},
number = {SUPPL. 1},
pages = {3--30},
url = {http://dx.doi.org/10.1002/qj.752},
doi = {https://doi.org/10.1002/qj.752}
}

Yan, X., Ducrocq, V., Poli, P., Jaubert, G., Walpersdorf, A., Fourier, J. and Maison, G. Advances in Geosciences Mesoscale GPS Zenith Delay assimilation during a Mediterranean heavy precipitation event 2008 Advances In Geosciences
Vol. 17, pp. 71-77
article
BibTeX:
@article{Yan2008a,
author = {Yan, X and Ducrocq, V and Poli, P and Jaubert, G and Walpersdorf, A and Fourier, Joseph and Maison, G},
title = {Advances in Geosciences Mesoscale GPS Zenith Delay assimilation during a Mediterranean heavy precipitation event},
journal = {Advances In Geosciences},
year = {2008},
volume = {17},
pages = {71--77}
}

Yan, X., Ducrocq, V., Poli, P., Hakam, M., Jaubert, G. and Walpersdorf, A. Impact of GPS zenith delay assimilation on convective-scale prediction of Mediterranean heavy rainfall 2009 Journal of Geophysical Research Atmospheres
Vol. 114(3)
article DOI URL
BibTeX:
@article{Yan2009,
author = {Yan, X. and Ducrocq, V. and Poli, P. and Hakam, M. and Jaubert, G. and Walpersdorf, A.},
title = {Impact of GPS zenith delay assimilation on convective-scale prediction of Mediterranean heavy rainfall},
journal = {Journal of Geophysical Research Atmospheres},
publisher = {Wiley-Blackwell},
year = {2009},
volume = {114},
number = {3},
url = {http://dx.doi.org/10.1029/2008jd011036},
doi = {https://doi.org/10.1029/2008JD011036}
}

Yan, X., Ducrocq, V., Jaubert, G., Brousseau, P., Poli, P., Champollion, C., Flamant, C. and Boniface, K. The benefit of GPS zenith delay assimilation to high-resolution quantitative precipitation forecasts: A case-study from COPS IOP 9 2009 Quarterly Journal of the Royal Meteorological Society
Vol. 135(644), pp. 1788-1800
article DOI URL
BibTeX:
@article{Yan2009b,
author = {Yan, X. and Ducrocq, V. and Jaubert, G. and Brousseau, P. and Poli, P. and Champollion, C. and Flamant, C. and Boniface, K.},
title = {The benefit of GPS zenith delay assimilation to high-resolution quantitative precipitation forecasts: A case-study from COPS IOP 9},
journal = {Quarterly Journal of the Royal Meteorological Society},
publisher = {Wiley-Blackwell},
year = {2009},
volume = {135},
number = {644},
pages = {1788--1800},
url = {http://dx.doi.org/10.1002/qj.508},
doi = {https://doi.org/10.1002/qj.508}
}

Zhang, S.-R., Erickson, P.J., Vierinen, J., Aa, E., Rideout, W., Coster, A.J. and Goncharenko, L.P. Conjugate Ionospheric Perturbation During the 2017 Solar Eclipse 2021 Journal of Geophysical Research (Space Physics)
Vol. 126(2), pp. e28531
article DOI
Abstract: We report new findings of total electron content (TEC) perturbations in
the southern hemisphere at conjugate locations to the northern
eclipse on August 21, 2017. We identified a persistent conjugate
TEC depletion by 10%-15% during the eclipse time, elongating
along magnetic latitudes with at least
\sim5textdegree latitudinal width. As the
Moon's shadow swept southward, this conjugate depletion moved
northward and became most pronounced at lower magnetic latitudes
(gt-20textdegreeN). This depletion was coincident with a
weakening of the southern crest of the equatorial ionization
anomaly (EIA), while the northern EIA crest stayed almost
undisturbed or was slightly enhanced. We suggest these conjugate
perturbations were associated with dramatic eclipse initiated
plasma pressure reductions in the flux tubes, with a large
portion of shorter tubes located at low latitudes underneath the
Moon's shadow. These short L shell tubes intersect with the F
region ionosphere at low and equatorial latitudes. The plasma
pressure gradient was markedly skewed northward in the flux
tubes at low and equatorial latitudes, as was the neutral
pressure. These effects caused a general northward motion
tendency for plasma within the flux tubes, and inhibited normal
southward diffusion of equatorial fountain plasma into the
southern EIA region. We also identified posteclipse ionospheric
disturbances likely associated with the global propagation of
eclipse induced traveling atmospheric disturbances in alignment
with the Moon's shadow moving direction.
BibTeX:
@article{Zhang2021,
author = {Zhang, Shun-Rong and Erickson, Philip J. and Vierinen, Juha and Aa, Ercha and Rideout, William and Coster, Anthea J. and Goncharenko, Larisa P.},
title = {Conjugate Ionospheric Perturbation During the 2017 Solar Eclipse},
journal = {Journal of Geophysical Research (Space Physics)},
year = {2021},
volume = {126},
number = {2},
pages = {e28531},
doi = {https://doi.org/10.1029/2020JA028531}
}