Centre dedocumentation
scientifique

Inclusion of GPS clock estimates for satellites Sentinel-3A/3B in DORIS geodetic solutions / Petr Štěpánek in Journal of geodesy, vol 94 n° 12 (December 2020)  

Public [article]  inJournal of geodesy > vol 94 n° 12 (December 2020) . - n° 116 Titre : Inclusion of GPS clock estimates for satellites Sentinel-3A/3B in DORIS geodetic solutions Type de document : Article/Communication Auteurs : Petr Štěpánek, Auteur ; Duan Bingbing, Auteur ; Filler Vratislav, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : n° 116 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] Atlantique Sud [Termes descripteurs IGN] Cryosat [Termes descripteurs IGN] décalage d'horloge [Termes descripteurs IGN] données DORIS [Termes descripteurs IGN] horloge du récepteur [Termes descripteurs IGN] Jason [Termes descripteurs IGN] oscillateur [Termes descripteurs IGN] récepteur DORIS [Termes descripteurs IGN] récepteur GPS [Termes descripteurs IGN] rotation de la Terre [Termes descripteurs IGN] SARAL [Termes descripteurs IGN] Sentinel-3 Résumé : (auteur) A unique architecture of Sentinel-3A and Sentinel-3B satellites includes the shared ultra-stable oscillator (USO) by the DORIS and GPS receivers. This concept enables to apply onboard GPS clock estimates in the DORIS processing substituting the DORIS polynomial clock model by the GPS epoch-wise model, together with a DORIS-specific clock offset. Such an approach is particularly profitable for the mitigation of the South Atlantic Anomaly (SAA) effect affecting the short-term frequency stability of the USO oscillator in the South America and South Atlantic region. The GPS clock behavior precisely maps the SAA effect and enables us to demonstrate a difference of the USO sensitivity to the SAA for Sentinel-3A and Sentinel-3B. We present world grid maps of clock time derivatives for both Sentinels, displaying a different sign of the direct effect and other differences in the USO memory/recovery effect. Moreover, we present the impact of SAA on 3D positioning where the largest SAA-related bias reaches several centimeters. We also determine an effect of the precise clock modeling on the Earth rotation parameter estimates. In addition to these improvements, the elimination of the SAA effect gives us an opportunity to get an almost SAA-free DORIS solution from Sentinel-3A and Sentinel-3B satellites. Using the combined solution of both Sentinels as a reference, we estimate the SAA effect on the DORIS beacon positions also for satellites Jason-2, Jason-3, Saral, Cryosat-2 and Hy-2A and find significant positioning biases for all the recent satellites except Saral. Numéro de notice : A2020-737 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01428-x date de publication en ligne : 18/11/2020 En ligne : https://doi.org/10.1007/s00190-020-01428-x Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96353 [article]

Assessment of salt marsh change on Assateague Island National Seashore between 1962 and 2016 / Anthony Campbell in Photogrammetric Engineering & Remote Sensing, PERS, vol 86 n° 3 (March 2020)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 86 n° 3 (March 2020) . - pp 187 - 194 Titre : Assessment of salt marsh change on Assateague Island National Seashore between 1962 and 2016 Type de document : Article/Communication Auteurs : Anthony Campbell, Auteur ; Yeqiao Wang, Auteur Année de publication : 2020 Article en page(s) : pp 187 - 194 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes descripteurs IGN] analyse d'image orientée objet [Termes descripteurs IGN] analyse diachronique [Termes descripteurs IGN] approche hiérarchique [Termes descripteurs IGN] Atlantique (océan) [Termes descripteurs IGN] biodiversité [Termes descripteurs IGN] cartographie thématique [Termes descripteurs IGN] détection de changement [Termes descripteurs IGN] Etats-Unis [Termes descripteurs IGN] image à très haute résolution [Termes descripteurs IGN] image satellite [Termes descripteurs IGN] lidar bathymétrique [Termes descripteurs IGN] littoral [Termes descripteurs IGN] marais salant [Termes descripteurs IGN] montée du niveau de la mer [Termes descripteurs IGN] service écosystémique [Termes descripteurs IGN] surveillance du littoral Résumé : (auteur) Salt marshes provide extensive ecosystem services, including high biodiversity, denitrification, and wave attenuation. In the mid-Atlantic, sea level rise is predicted to affect salt marsh ecosystems severely. This study mapped the entirety of Assateague Island with Very High Resolution satellite imagery and object-based methods to determine an accurate salt marsh baseline for change analysis. Topobathy-metric light detection and ranging was used to map the salt marsh and model expected tidal effects. The satellite imagery, collected in 2016 and classified at two hierarchical thematic schemes, were compared to determine appropriate thematic richness. Change analysis between this 2016 map and both a manually delineated 1962 salt marsh extent and image classification of the island from 1994 determined rates off change. The study found that from 1962 to 1994, salt marsh expanded by 4.01 ha/year, and from 1994 to 2016 salt marsh was lost at a rate of -3.4 ha/ year. The study found that salt marsh composition, (percent vegetated salt marsh) was significantly influenced by elevation, the length of mosquito ditches, and starting salt marsh composition. The study illustrates the importance of remote sensing monitoring for understanding site-specific changes to salt marsh environments and the barrier island system. Numéro de notice : A2020-148 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.14358/PERS.86.3.187 date de publication en ligne : 01/03/2020 En ligne : https://doi.org/10.14358/PERS.86.3.187 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94777 [article]

Validation of marine geoid models by utilizing hydrodynamic model and shipborne GNSS profiles / Sander Varbla in Marine geodesy, Vol 43 n° 2 (March 2020)  

Public [article]  inMarine geodesy > Vol 43 n° 2 (March 2020) . - pp 134 - 162 Titre : Validation of marine geoid models by utilizing hydrodynamic model and shipborne GNSS profiles Type de document : Article/Communication Auteurs : Sander Varbla, Auteur ; Artu Ellmann, Auteur ; Nicole Delpeche-Ellmann, Auteur Année de publication : 2020 Article en page(s) : pp 134 - 162 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] Baltique, mer [Termes descripteurs IGN] données marégraphiques [Termes descripteurs IGN] force de gravitation [Termes descripteurs IGN] geoïde marin [Termes descripteurs IGN] instrument embarqué [Termes descripteurs IGN] instrumentation GNSS [Termes descripteurs IGN] levé gravimétrique [Termes descripteurs IGN] navire [Termes descripteurs IGN] niveau de la mer [Termes descripteurs IGN] simulation hydrodynamique Résumé : (auteur) An essential role of the FAMOS international cooperation project is to obtain new marine gravity observations over the Baltic Sea for improving gravimetric geoid modelling. To achieve targeted 5 cm modelling accuracy, it is important to acquire new gravimetric data, as the existing data over some regions are inaccurate and sparse. As the accuracy of contemporary geoid models over marine areas remains unknown, it is important to evaluate geoid modelling outcome by independent data. Thus, this study presents results of a shipborne marine gravity and GNSS campaign for validation of existing geoid models conducted in the eastern section of the Baltic Sea. Challenging aspects for utilizing shipborne GNSS profiles tend to be with quantifying vessel’s attitude, processing of noise in the data and referencing to the required datum. Consequently, the novelty of this study is in the development of methodology that considers the above-mentioned challenges. In addition, tide gauge records in conjunction with an operational hydrodynamic model are used to identify offshore sea level dynamics during the marine measurements. The results show improvements in geoid modelling due to new marine gravimetric data. It is concluded that the marine GNSS profiles can potentially provide complementary constraints in problematic geoid modelling areas. Numéro de notice : A2020-051 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/01490419.2019.1701153 date de publication en ligne : 20/01/2020 En ligne : https://doi.org/10.1080/01490419.2019.1701153 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94918 [article]

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)  

Public [article]  inGlobal and Planetary Change > vol 165 (June 2018) . - pp 1 - 12 Titre : Post-1980 shifts in the sensitivity of boreal tree growth to North Atlantic Ocean dynamics and seasonal climate Type de document : Article/Communication Auteurs : Clémentine Ols , Auteur ; Valérie Trouet, Auteur ; Martin P. Girardin, Auteur ; Annika Hofgaard, Auteur ; Yves Bergeron, Auteur ; Igor Drobyshev, Auteur Année de publication : 2018 Projets : 3-projet - voir note / Article en page(s) : pp 1 - 12 Note générale : bibliographie This study was financed by the Natural Sciences and Engineering Research Council of Canada (NSERC) through the project ‘Naturaldisturbances, forest resilience and forest management: the study case of the northern limit for timber allocation in Quebec in a climate change context’(STPGP 413444-11). Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] analyse de sensibilité [Termes descripteurs IGN] Atlantique Nord [Termes descripteurs IGN] cerne [Termes descripteurs IGN] circulation océanique [Termes descripteurs IGN] climat [Termes descripteurs IGN] croissance végétale [Termes descripteurs IGN] dendrochronologie [Termes descripteurs IGN] forêt boréale [Termes descripteurs IGN] inventaire forestier étranger (données) [Termes descripteurs IGN] océanographie dynamique [Termes descripteurs IGN] Picea abies [Termes descripteurs IGN] picea mariana [Termes descripteurs IGN] puits de carbone [Termes descripteurs IGN] Québec (Canada) [Termes descripteurs IGN] Suède [Vedettes matières IGN] Végétation et changement climatique Résumé : (auteur) The mid-20th century changes in North Atlantic Ocean dynamics, e.g. slow-down of the Atlantic meridional overturning thermohaline circulation (AMOC), have been considered as early signs of tipping points in the Earth climate system. We hypothesized that these changes have significantly altered boreal forest growth dynamics in northeastern North America (NA) and northern Europe (NE), two areas geographically adjacent to the North Atlantic Ocean. To test our hypothesis, we investigated tree growth responses to seasonal large-scale oceanic and atmospheric indices (the AMOC, North Atlantic Oscillation (NAO), and Arctic Oscillation (AO)) and climate (temperature and precipitation) from 1950 onwards, both at the regional and local levels. We developed a network of 6876 black spruce (NA) and 14437 Norway spruce (NE) tree-ring width series, extracted from forest inventory databases. Analyses revealed post-1980 shifts from insignificant to significant tree growth responses to summer oceanic and atmospheric dynamics both in NA (negative responses to NAO and AO indices) and NE (positive response to NAO and AMOC indices). The strength and sign of these responses varied, however, through space with stronger responses in western and central boreal Quebec and in central and northern boreal Sweden, and across scales with stronger responses at the regional level than at the local level. Emerging post-1980 associations with North Atlantic Ocean dynamics synchronized with stronger tree growth responses to local seasonal climate, particularly to winter temperatures. Our results suggest that ongoing and future anomalies in oceanic and atmospheric dynamics may impact forest growth and carbon sequestration to a greater extent than previously thought. Cross-scale differences in responses to North Atlantic Ocean dynamics highlight complex interplays in the effects of local climate and ocean-atmosphere dynamics on tree growth processes and advocate for the use of different spatial scales in climate-growth research to better understand factors controlling tree growth. Numéro de notice : A2018-662 Affiliation des auteurs : LIF+Ext (2012-2019) Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.gloplacha.2018.03.006 date de publication en ligne : 18/03/2018 En ligne : https://doi.org/10.1016/j.gloplacha.2018.03.006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93844 [article]

Estimated location of the seafloor sources of marine natural oil seeps from sea surface outbreaks : A new "source path procedure" applied to the northern Gulf of Mexico / Zhour Najoui in Marine and Petroleum Geology, Vol 91 (March 2018)  

Public [article]  inMarine and Petroleum Geology > Vol 91 (March 2018) . - pp 190 - 201 Titre : Estimated location of the seafloor sources of marine natural oil seeps from sea surface outbreaks : A new "source path procedure" applied to the northern Gulf of Mexico Type de document : Article/Communication Auteurs : Zhour Najoui, Auteur ; Serge Riazanoff, Auteur ; Benoit Deffontaines , Auteur ; Jean-Paul Xavier, Auteur Année de publication : 2018 Projets : 3-projet - voir note / Article en page(s) : pp 190 - 201 Note générale : Bibliographie This work is performed as a part of a PhD research program funded by VisioTerra/UPE (Université Paris-Est) and ANRT/CIFRE (N° 2013/1252). Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes descripteurs IGN] fond marin [Termes descripteurs IGN] HYbrid Coordinate Ocean Model [Termes descripteurs IGN] image radar moirée [Termes descripteurs IGN] Mexique (golfe du) [Termes descripteurs IGN] modèle stochastique [Termes descripteurs IGN] pétrole Résumé : (Auteur) Marine oil reservoirs are generally characterized on the sea surface by the presence of natural oil seeps (Sea Surface outbreaks - hereafter SSO). The latter are easily evidenced with Synthetic Aperture Radar (SAR) images because of the dampening effect that oil has on the capillary and associated small gravity waves (Bragg waves). The sea surface outbreaks of oil seeps are offset from their source on the seabed (seafloor sources - SFS) by hundreds meters or even kilometres. This displacement all along the sea water column is a function of the upward velocity of the oil droplet size, and the presence of lateral marine currents. This paper proposes a Vertical Drift Model (VDM) that combines both SAR images to get the SSO and the hydrodynamic model (HYCOM) function of the oil droplet size to estimate the SFS. After oil seeps detection from SAR images, the VDM proceeds to a regression in time and space based on the upward velocity of the oil, based on Stokes law, and the hydrodynamic conditions (HYCOM) to estimate the location of the seep source on the seafloor. The upward velocity depends strongly on the unknown droplet size. We propose herein a new VDM method named "sources paths" that allows to estimate the oil seeps sources on the seafloor without a priori knowledge of the oil droplet size by finding, for each oil seep, the seafloor sources corresponding to different diameters. We call "sources path" the line that joins the seafloor sources for an oil seep. The seafloor sources ought to be at the intersection of the maximum sources paths. The methodology has been applied to the northern Gulf of Mexico where the locations of many prolific oil seep sites are well known. A first validation of the source path procedure is that the obtained SFSs correspond to the seafloor sources of oil droplets having the same diameter and seeped at different times. Another validation has been performed through the comparison of SFS locations and those of the outcropping shallow salt. This comparison shows a good correlation and suggests that the oil seeps may be situated above the allochtonous toward autochthonous salt connections. Numéro de notice : A2018-064 Affiliation des auteurs : LaSTIG LAREG+Ext (2012-mi2018) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.marpetgeo.2017.12.035 date de publication en ligne : 04/01/2018 En ligne : https://doi.org/10.1016/j.marpetgeo.2017.12.035 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89404 [article]

Baltic sea ice concentration estimation using SENTINEL-1 SAR and AMSR2 microwave radiometer data / Juha Karvonen in IEEE Transactions on geoscience and remote sensing, vol 55 n° 5 (May 2017)  

Permalink

Is the Jason-2 DORIS oscillator also affected by the South Atlantic Anomaly? / Pascal Willis in Advances in space research, vol 58 n° 12 (15 December 2016)  

Permalink

Impact of the North Atlantic oscillation on Southern Europe water distribution: insights from geodetic data / Pierre Valty in Earth Interactions, vol 19 n° 10 (September 2015)    

Permalink

Lasergrammétrie sous-marine / Yann Morel (2015) 

Permalink

Aires marines protégées de l'Atlantique : vers une convergence des données (?) : l'exemple OSPAR - MAIA - PANACHE / Christian Carolin in Géomatique expert, n° 101 (novembre - décembre 2014) 

Permalink

Les effets de l'oscillation Nord-Atlantique sur les transferts de masse, vus par géodésie / Pierre Valty in XYZ, n° 139 (juin - août 2014)

Permalink

The impact of the dynamic sea surface topography on the quasi-geoid in shallow coastal waters / D.C. Slobbe in Journal of geodesy, vol 88 n° 3 (March 2014)  

Permalink

Lowest astronomical tide in the North Sea derived from a vertically referenced shallow water model, and an assessment of its suggested sense of safety / D. Slobbe in Marine geodesy, vol 36 n° 1 (January - March 2013)  

Permalink

Quantifying urban land cover change between 2001 and 2006 in the Gulf of Mexico region / G. Xian in Geocarto international, vol 27 n° 6 (October 2012)  

Permalink

Reconstruction des séries marégraphiques de la mer du Nord et de Norvège / Raphaël Baucry (2012) 

Permalink