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Comparison and evaluation of high-resolution marine gravity recovery via sea surface heights or sea surface slopes / Shengjun Zhang in Journal of geodesy, vol 95 n° 6 (June 2021)  

Public [article]  inJournal of geodesy > vol 95 n° 6 (June 2021) . - n° 66 Titre : Comparison and evaluation of high-resolution marine gravity recovery via sea surface heights or sea surface slopes Type de document : Article/Communication Auteurs : Shengjun Zhang, Auteur ; Adili Abulaitijiang, Auteur ; Ole Baltazar Andersen, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : n° 66 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] données altimétriques [Termes IGN] données Jason [Termes IGN] géodésie marine [Termes IGN] gravimétrie en mer [Termes IGN] hauteurs de mer [Termes IGN] image Cryosat [Termes IGN] relief sous-marin [Termes IGN] SARAL [Termes IGN] série temporelle [Termes IGN] surface de la mer Résumé : (auteur) There are two dominating approaches of modeling the marine gravity field based on satellite altimetry observations. In this study, the marine gravity field is determined in four selected areas (Northwestern Atlantic, Hawaii ocean area, Mariana Trench area, and Aegean Sea) by using exact same input datasets but different methods which are based on sea surface height (SSH) and sea surface slope (SSS), respectively. The impact of the methodology is evaluated by conducting validations with shipborne gravity observation. The CryoSat-2, Jason-1/2, and SARAL/Altika geodetic mission data (similarly 3-year-long time series) are firstly retracked by the two-pass retracker. After that, the obtained SSHs are used for the derivation of geoid undulations and vertical deflections, and then for the resulting marine gravity field separately. The validation results indicate that the SSH-based method has advantages in robustly estimating marine gravity anomalies near the coastal zone. The SSS-based method has advantages over regions with intermedium ocean depths (2000–4000 m) where seamounts and ridges are found, but obvious disadvantages when the ocean currents flow along the north–south direction (e.g., western boundary currents) or the topography features north–south directional trenches. In the deep ocean where the seafloor topography is plain and smooth, the two methods have similar accuracy. Numéro de notice : A2021-433 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-021-01506-8 Date de publication en ligne : 27/05/2021 En ligne : https://doi.org/10.1007/s00190-021-01506-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97799 [article]

Discrimination of different sea ice types from CryoSat-2 satellite data using an Object-based Random Forest (ORF) / Su Shu in Marine geodesy, Vol 43 n° 3 (May 2020)  

Public [article]  inMarine geodesy > Vol 43 n° 3 (May 2020) . - pp 213 - 233 Titre : Discrimination of different sea ice types from CryoSat-2 satellite data using an Object-based Random Forest (ORF) Type de document : Article/Communication Auteurs : Su Shu, Auteur ; Xinghua Zhou, Auteur ; Zhanchi Liu, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 213 - 233 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] Arctique, océan [Termes IGN] classification orientée objet [Termes IGN] classification par forêts d'arbres décisionnels [Termes IGN] forme d'onde [Termes IGN] glace de mer [Termes IGN] image Cryosat Résumé : (Auteur) Sea ice type is one of the most sensitive variables in Arctic sea ice monitoring, and it is important for the retrieval of ice thickness. In this study, we analyzed various waveform features that characterize the echo waveform shape and Sigma0 (i.e., backscatter coefficient) of CryoSat-2 synthetic aperture radar altimeter data over different sea ice types. Arctic and Antarctic Research Institute operational ice charts were input as reference. An object-based random forest (ORF) classification method is proposed with overall classification accuracy of 90.1%. Accuracy of 92.7% was achieved for first-year ice (FYI), which is the domain ice type in the Arctic. Accuracy of 76.7% was achieved at the border of FYI and multiyear ice (MYI), which is better than current state-of-the-art methods. Accuracy of 83.8% was achieved for MYI. Results showed the overall accuracy of the ORF method was increased by ∼8% in comparison with other methods, and the classification accuracy at the border of FYI and MYI was increased by ∼10.5%. Nevertheless, ORF classification performance might be influenced by the selected waveform features, snow loading, and the ability to distinguish sea ice from leads. Numéro de notice : A2020-183 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01490419.2019.1671560 Date de publication en ligne : 21/10/2019 En ligne : https://doi.org/10.1080/01490419.2019.1671560 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94971 [article]

Arctic sea ice thickness retrievals from CryoSat-2: seasonal and interannual comparisons of three different products / Mengmeng Li in International Journal of Remote Sensing IJRS, vol 41 n° 1 (01 - 08 janvier 2020)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 41 n° 1 (01 - 08 janvier 2020) . - pp 152 - 170 Titre : Arctic sea ice thickness retrievals from CryoSat-2: seasonal and interannual comparisons of three different products Type de document : Article/Communication Auteurs : Mengmeng Li, Auteur ; Chang-qing Ke, Auteur ; Hongjie Xie, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 152 - 170 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] analyse comparative [Termes IGN] Arctique, océan [Termes IGN] changement climatique [Termes IGN] épaisseur de la glace [Termes IGN] forme d'onde [Termes IGN] glace de mer [Termes IGN] image Cryosat [Termes IGN] variation saisonnière Résumé : (auteur) As a fundamental climate state variable, sea ice thickness (SIT) has exhibited a declining trend over the past five decades. Here, we present a quantitative comparison of three CryoSat-2 (CS-2) SIT products from the Alfred-Wegener-Institute (AWI), the National Snow and Ice Data Centre (NSIDC), and the European Space Agency (ESA) during the growth season (October to April) from 2010 to 2018 with Operation IceBridge (OIB) data. The results show that the NSIDC SIT product is the closest to the OIB SIT, with ESA SIT exhibiting the highest bias. During each growth season, the SIT differences between AWI and NSIDC gradually decrease, while such differences between ESA and NSIDC increase for first-year ice (FYI) and decrease then increase for multiyear ice (MYI). The difference between ESA and NSIDC is larger than that between AWI and NSIDC. Moreover, the rather large differences between ESA and NSIDC are mainly located in thin ice areas. Consistent to SIT comparative results, sea ice freeboard for ESA is higher than that for OIB, AWI and NSIDC, especially FYI freeboard. Sea ice freeboard for NSIDC is the closest to that for OIB. The comparative results indicate that the sources of the differences in SIT between the products mainly originate from the sea ice density and freeboard retrieval methods. The choices of different waveform retrackers and threshold assignments significantly influence the MYI freeboard retrievals due to the relatively thick snow depth and high surface roughness over MYI. Numéro de notice : A2020-211 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1080/01431161.2019.1637961 Date de publication en ligne : 02/07/2019 En ligne : https://doi.org/10.1080/01431161.2019.1637961 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94893 [article]

Satellite altimetry for earth sciences / Frédéric Frappart (2019)  

Public Titre : Satellite altimetry for earth sciences Type de document : Monographie Auteurs : Frédéric Frappart, Éditeur scientifique ; Ole Andersen, Éditeur scientifique ; Sergey Lebedev, Éditeur scientifique ; Guillaume Ramillien, Éditeur scientifique Editeur : Bâle [Suisse] : Multidisciplinary Digital Publishing Institute MDPI Année de publication : 2019 Importance : 484 p. ISBN/ISSN/EAN : 978-3-03897-681-3 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] altimétrie satellitaire par radar [Termes IGN] bande K [Termes IGN] classification non dirigée [Termes IGN] données GRACE [Termes IGN] image Cryosat [Termes IGN] image Envisat-ASAR [Termes IGN] image Sentinel-3 [Termes IGN] niveau de l'eau [Termes IGN] océanographie spatiale [Termes IGN] série temporelle Résumé : (Editeur) Satellite altimetry is a radar technique for measuring the topography of the Earth’s surface. It was initially designed for measuring the ocean’s topography, with reference to an ellipsoid, and for the determination of the marine geoid. Satellite altimetry has provided extremely valuable information on ocean science (e.g., circulation surface geostrophic currents, eddy structures, wave heights, and the propagation of oceanic Kelvin and Rossby waves). With more than 25 years of observations, it is also becoming vital to climate research, providing accurate measurements of sea level variations from regional to global scales. Altimetry has also demonstrated a strong potential for geophysical, cryospheric, and hydrological research and is now commonly used for the monitoring of Arctic and Antarctic ice sheet topography and of terrestrial surface water levels. This book aims to present reviews and recent advances of general interest in the use of radar altimetry in Earth sciences. Manuscripts are related to any aspect of radar altimetry technique or geophysical applications. We also encourage manuscripts resulting from the application of new altimetric technology (SAR, SARin, and Ka band) and improvements expected from missions to be launched in the near future (i.e., SWOT). Numéro de notice : 26304 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Monographie DOI : 10.3390/books978-3-03897-681-3 Date de publication en ligne : 28/08/2019 En ligne : https://doi.org/10.3390/books978-3-03897-681-3 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95062

The Use of remote sensing in hydrology / Frédéric Frappart (2018)  

Public Titre : The Use of remote sensing in hydrology Type de document : Monographie Auteurs : Frédéric Frappart, Éditeur scientifique Editeur : Bâle [Suisse] : Multidisciplinary Digital Publishing Institute MDPI Année de publication : 2018 Importance : 258 p. Format : 17 x 25 cm ISBN/ISSN/EAN : 978-3-03842-910-4 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] capteur spatial [Termes IGN] carte hydrographique [Termes IGN] évapotranspiration [Termes IGN] humidité du sol [Termes IGN] hydrodynamique [Termes IGN] hydrologie [Termes IGN] image Cryosat [Termes IGN] image Sentinel-SAR [Termes IGN] inondation [Termes IGN] modèle hydrographique [Termes IGN] précipitation [Termes IGN] stockage [Termes IGN] surveillance hydrologique Résumé : (éditeur) Remotely sensed data are nowadays commonly used for regional/global monitoring of hydrological variables including soil moisture, rainfall, water levels, flood extent, evapotranspiration or land water storage, as well as the forcing, calibration and assimilation into hydrodynamic, hydrological and hydrometeorological models. In the years to come, recent and future satellite sensors, some of them specifically designed for hydrological purposes, will provide systematic observations of hydrological parameters (e.g., surface and sub-surface storage and flux) at high spatial and temporal resolutions. This will offer new applications for the hydrological community. This book presents reviews and recent advances of general interest regarding the use of remote sensing for hydrology. The chapters are related to any hydrological reservoir (e.g., surface storage, soil moisture, groundwater, etc.) or flux (e.g., rainfall, evapotranspiration, discharge, etc.), the integration of satellite data into hydrological models, and the improvements to hydrology that can be expected from future satellite missions. Numéro de notice : 25962 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Monographie DOI : 10.3390/books978-3-03842-910-4 En ligne : https://doi.org/10.3390/books978-3-03842-910-4 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96538

Télédétection et changement climatique : l'exemple de l'Arctique / Claude Kergomard in Photo interprétation, vol 43 n° 4 (Décembre 2007)

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The Cryosat data products: their generation, in-situ validation and applications / R. Francis in ESA bulletin, n° 122 (May 2005)  

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