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Improved arctic ocean mass variability inferred from time-variable gravity with constraints and dual leakage correction / Dapeng Mu in Marine geodesy, Vol 43 n° 3 (May 2020)  

Public [article]  inMarine geodesy > Vol 43 n° 3 (May 2020) . - pp 269 - 284 Titre : Improved arctic ocean mass variability inferred from time-variable gravity with constraints and dual leakage correction Type de document : Article/Communication Auteurs : Dapeng Mu, Auteur ; Tianhe Xu, Auteur ; Guochang Xu, Auteur Année de publication : 2020 Article en page(s) : pp 269 - 284 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] Arctique, océan [Termes descripteurs IGN] données GRACE [Termes descripteurs IGN] harmonique sphérique [Termes descripteurs IGN] marée océanique Résumé : (Auteur) The ocean mass variability inferred from Gravity Recovery and Climate Experiment (GRACE) satellites mission is challenged by the stripes and the leakage across land-ocean boundary. The recently released GRACE mascons solutions are advanced by applying constraints that remove efficiently the stripes and dual leakage correction that restores the coastal ocean mass variability. Here we quantitatively evaluate the improvement in the Arctic Ocean mass variability by GRACE mascons. To do so, we compare the combination of GRACE solutions (including the mascons solutions and traditional spherical harmonic coefficients (SHCs) solutions) and the steric estimates against the altimeter observations. Our results suggest that mascons solutions produce stronger correlations compared to SHCs solutions, especially along the coastal zone, indicating the importance of the dual leakage correction. Stronger correlation is produced by the mascons over a small basin in the interior of the Arctic Ocean, suggesting that mascons solutions deliver better ocean mass variability than the SHCs solutions. Since the comparisons are carried out over two sub-basins, we conclude that mascons are able to provide better regional ocean mass variability that may have implications for regional sea level budget, in particular over the coastal zone. Numéro de notice : A2020-185 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01490419.2020.1711832 date de publication en ligne : 17/01/2020 En ligne : https://doi.org/10.1080/01490419.2020.1711832 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94975 [article]

Polarization dependence of azimuth cutoff from quad-pol SAR images / Huimin Li in IEEE Transactions on geoscience and remote sensing, vol 57 n° 12 (December 2019)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 57 n° 12 (December 2019) . - pp 9878 - 9887 Titre : Polarization dependence of azimuth cutoff from quad-pol SAR images Type de document : Article/Communication Auteurs : Huimin Li, Auteur ; Alexis Mouche, Auteur ; He Wang, Auteur ; Justin E. Stopa, Auteur ; Bertrand Chapron, Auteur Année de publication : 2019 Article en page(s) : pp 9878 - 9887 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes descripteurs IGN] angle d'incidence [Termes descripteurs IGN] azimut [Termes descripteurs IGN] données polarimétriques [Termes descripteurs IGN] image Gaofen [Termes descripteurs IGN] image radar moirée [Termes descripteurs IGN] image Radarsat [Termes descripteurs IGN] polarisation [Termes descripteurs IGN] polarisation croisée [Termes descripteurs IGN] surface de la mer [Termes descripteurs IGN] transformation non linéaire [Termes descripteurs IGN] vague Résumé : (auteur) Although basic understanding of the synthetic aperture radar (SAR) imaging mechanism of ocean waves has been achieved, challenges still remain. In this paper, a large number of quad-polarized SAR images are analyzed to help assess how the standard SAR imaging transformation applies to all polarization channels. Foremost, the azimuth cutoff, a parameter essentially governed by the detected wave motions, is today solely related to radar configuration and the ocean wave spectrum but not to the polarization configuration. As obtained, the analyses based on quad-polarized Radarsat-2 and Gaofen-3 products document the distinct dependence of azimuth cutoff on polarization and incidence angle. Especially for cross-polarized VH measurements, azimuth cutoff estimates are generally larger than copolarized HH ones, the latter already being larger than values estimated under VV configuration. This trend increases with the incidence angle. The systematic comparisons between SAR measurements and simulations further demonstrate that the present SAR nonlinear transformation may not properly take into account the differing coherence time associated with the multi-polarized observation of ocean scenes. In particular, to reproduce the large azimuth cutoff parameters of cross-polarized images, a reduced coherence time shall be expected. This measurable sensitivity shall enhance the capabilities of polarized SAR systems to precisely derive more ocean surface properties, especially the influence of wave breakers, by combining both the copolarization and cross-polarization measurements. Numéro de notice : A2019-601 Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2019.2929835 date de publication en ligne : 14/08/2019 En ligne : http://doi.org/10.1109/TGRS.2019.2929835 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94602 [article]

Introducing a vertical land motion model for improving estimates of sea level rates derived from tide gauge records affected by earthquakes / Anna Klos in GPS solutions, vol 23 n° 4 (October 2019)  

Public [article]  inGPS solutions > vol 23 n° 4 (October 2019) Titre : Introducing a vertical land motion model for improving estimates of sea level rates derived from tide gauge records affected by earthquakes Type de document : Article/Communication Auteurs : Anna Klos, Auteur ; Jürgen Kusche, Auteur ; L. Fenoglio-Marc, Auteur ; et al., Auteur Année de publication : 2019 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes descripteurs IGN] changement du niveau de la mer [Termes descripteurs IGN] déformation verticale de la croute terrestre [Termes descripteurs IGN] données marégraphiques [Termes descripteurs IGN] marée océanique [Termes descripteurs IGN] modèle de simulation [Termes descripteurs IGN] niveau de la mer [Termes descripteurs IGN] Pacifique (océan) [Termes descripteurs IGN] positionnement par GPS [Termes descripteurs IGN] séisme [Termes descripteurs IGN] série temporelle Résumé : (Auteur) We reassess the absolute and relative sea level changes at 38 tide gauge stations in the earthquake-affected Western North Pacific for the 1993–2015 period, focusing on the vertical land motion (VLM) which is crucial for narrowing the gap between these estimates. In this area, simply discarding all earthquake-affected sites, one overestimates the average regional sea level rise by more than 0.5 mm/year. Disregarding VLM would lead to misestimating local sea level trends between 0.2 and 7.6 mm/year. If accounted for, but modeled as linear during the entire time span, VLM leads to regional absolute sea level rise errors of up to 0.4 mm/year. Therefore, we introduce a new methodology that better represents the Global Positioning System (GPS)-derived nonlinear VLM by accounting for co-seismic offsets, changes in the vertical velocities and post-seismic transient. Also, for the first time, a combination of white and power-law noises is added to this nonlinear model to derive proper uncertainties of VLM. We find a maximum difference of 15.3 mm/year between pre- and post-seismic vertical velocities. The GPS-sensed vertical co-seismic displacement approaches 36 mm. Assuming the changes in vertical velocities and displacement due to the tectonic movements is not accounted for, and then, estimating absolute sea level rise from tide gauges can result in an error of 10 mm/year. Introducing a new nonlinear VLM model improves absolute tide gauge sea level estimates by 20% on average. Finally, for the reconstructed Western North Pacific sea level, altimetry agrees best with tide gauge data corrected employing the new nonlinear VLM model. Numéro de notice : A2019-333 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-019-0896-1 date de publication en ligne : 24/07/2019 En ligne : https://doi.org/10.1007/s10291-019-0896-1 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93422 [article]

Analysis of ocean tide loading displacements by GPS kinematic precise point positioning: a case study at the China coastal site SHAO / H. Zhao in Survey review, vol 51 n° 365 (March 2019)  

Public [article]  inSurvey review > vol 51 n° 365 (March 2019) . - pp 172 - 182 Titre : Analysis of ocean tide loading displacements by GPS kinematic precise point positioning: a case study at the China coastal site SHAO Type de document : Article/Communication Auteurs : H. Zhao, Auteur ; Q. Zhang, Auteur ; R. Tu, Auteur ; Z. Liu, Auteur Année de publication : 2019 Article en page(s) : pp 172 - 182 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] analyse spectrale [Termes descripteurs IGN] Chine [Termes descripteurs IGN] données GPS [Termes descripteurs IGN] données marégraphiques [Termes descripteurs IGN] GPS en mode cinématique [Termes descripteurs IGN] littoral [Termes descripteurs IGN] marée océanique [Termes descripteurs IGN] positionnement ponctuel précis [Termes descripteurs IGN] série temporelle [Termes descripteurs IGN] surcharge océanique Résumé : (Auteur) Ocean tide loading (OTL) displacement amplitudes and phase lags of SHAO site are estimated by global positioning system (GPS), kinematic precise point positioning (PPP) and spectral analysis using 19 years of continuous GPS observations. In kinematic PPP, the 66 additional harmonic displacement parameters are replaced by the three time-varying displacement parameters without a priori modelled OTL displacements. By comparing the results with predictions from hybrid regional/global models, we are able to demonstrate that GPS/model agreements are at the level of 0.2 mm (horizontal) and 0.6 mm (vertical) for the four lunar constituents, 0.4 mm (horizontal) and 1.35 mm (vertical) for the four solar/sidereal constituents, and 0.2 mm (horizontal) and 0.3 mm (vertical) for the three long-period constituents. Finally, we conclude that GPS-derived lunar constituents can substitute for the model corrections in GPS data processing and the accuracy of GPS-derived solar/sidereal constituents needs to be improved by further studies. Numéro de notice : A2019-190 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2017.1407392 date de publication en ligne : 30/11/2017 En ligne : https://doi.org/10.1080/00396265.2017.1407392 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92634 [article]

Wave measurements with a modified HydroBall buoy using different GNSS processing strategies / Benoit Crépeau Gendron in Geomatica [en ligne], vol 73 n° 1 (March 2019)  

Public [article]  inGeomatica [en ligne] > vol 73 n° 1 (March 2019) . - pp 1 - 14. Titre : Wave measurements with a modified HydroBall buoy using different GNSS processing strategies Type de document : Article/Communication Auteurs : Benoit Crépeau Gendron, Auteur ; Mohamed Ali Chouaer, Auteur ; Rock Santerre, Auteur ; Mathieu Rondeau, Auteur ; Nicolas Seube, Auteur Année de publication : 2019 Article en page(s) : pp 1 - 14. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes descripteurs IGN] analyse comparative [Termes descripteurs IGN] bouée dérivante [Termes descripteurs IGN] mesure de précision [Termes descripteurs IGN] positionnement cinématique [Termes descripteurs IGN] positionnement ponctuel précis [Termes descripteurs IGN] positionnement relatif temporel [Termes descripteurs IGN] traitement de données GNSS [Termes descripteurs IGN] vague Résumé : (auteur) One of the CIDCO’s (The Interdisciplinary Center for the Development of Ocean Mapping) HydroBall® GNSS buoys has been specifically adapted to evaluate its potential for wave measurement at centimeter accuracy level. Multiple GNSS processing strategies were tested, namely PPK (Post-Processed Kinematic), PPP (Precise Point Positioning), and TRP (Time Relative Positioning). Experiments were carried out in a hydraulic flume where waves of different amplitudes and periods were generated in a controlled environment. The wave heights obtained by the various GNSS solutions were compared with ultrasonic gauge measurements placed along the flume. The best results were obtained with the PPK and TRP solutions with root mean squared (RMS) values of 2 cm (on average). The main advantages of the TRP solution are that it does not require any reference station nearby (contrary to PPK) or precise ephemerides (required by PPP). A sinusoidal regression comparison of the wave height time series allowed determination of the wave period and amplitude with mean errors of 0.06 s and 0.8 cm, respectively. Numéro de notice : A2019-543 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1139/geomat-2018-0021 date de publication en ligne : 15/04/2019 En ligne : https://doi.org/10.1139/geomat-2018-0021 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94184 [article]

Influence of subdaily model for polar motion on the estimated GPS satellite orbits / Natalia Panafidina in Journal of geodesy, vol 93 n° 2 (February 2019)  

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On the assimilation of absolute geodetic dynamic topography in a global ocean model: impact on the deep ocean state / Alexey Androsov in Journal of geodesy, vol 93 n° 2 (February 2019)  

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Advanced Remote Sensing Technology for Synthetic Aperture Radar Applications, Tsunami Disasters, and Infrastructure / Maged Marghany (2019)  

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Global observations of ocean surface winds and waves using spaceborne synthetic aperture radar measurements / Huimin Li (2019)  

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Post-1980 shifts in the sensitivity of boreal tree growth to North Atlantic Ocean dynamics and seasonal climate / Clémentine Ols in Global and Planetary Change, vol 165 (June 2018)  

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Improving the analysis of biogeochemical patterns associated with internal waves in the strait of Gibraltar using remote sensing images / Gabriel Navarro in Estuarine, Coastal and Shelf Science, vol 204 (May 2018)  

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Analysis of tsunami evacuation maps for a consensual symbolization rules proposal / Jean-François Girres in International journal of cartography, vol 4 n° 1 (March 2018)  

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MapMuxing : multiplexing cartographique pour la gestion de crise / Charlotte Hoarau (2018) 

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Reconstruction of time-varying tidal flat topography using optical remote sensing imageries / Kuo-Hsin Tseng in ISPRS Journal of photogrammetry and remote sensing, vol 131 (September 2017)  

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Analysis of decade-long time series of GPS-based polar motion estimates at 15-min temporal resolution / Aurore E. Sibois in Journal of geodesy, vol 91 n° 8 (August 2017)  

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