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Validation of Marine Geoid Models by Utilizing Hydrodynamic Model and Shipborne GNSS Profiles / Sandra Varbla in Marine geodesy, Vol 43 n° 1 (janvier 2020)  

Public [article]  inMarine geodesy > Vol 43 n° 1 (janvier 2020) . - 29 p. Titre : Validation of Marine Geoid Models by Utilizing Hydrodynamic Model and Shipborne GNSS Profiles Type de document : Article/Communication Auteurs : Sandra Varbla, Auteur ; Artu Ellmann, Auteur ; Nicole Delpeche-Ellmann, Auteur Année de publication : 2020 Article en page(s) : 29 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] Baltique, mer [Termes descripteurs IGN] carte marine [Termes descripteurs IGN] geoïde marin [Termes descripteurs IGN] gravimétrie en mer [Termes descripteurs IGN] hauteurs de mer [Termes descripteurs IGN] instrument embarqué [Termes descripteurs IGN] levé hydrographique [Termes descripteurs IGN] navire [Termes descripteurs IGN] niveau moyen des mers [Termes descripteurs IGN] quasi-géoïde [Termes descripteurs IGN] simulation hydrodynamique [Termes descripteurs IGN] traitement de données GNSS 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 : A2020-052 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern 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=94520 [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 Article en page(s) : pp 1 - 12 Note générale : bibliographie 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 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 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 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)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 55 n° 5 (May 2017) . - pp 2871 - 2883 Titre : Baltic sea ice concentration estimation using SENTINEL-1 SAR and AMSR2 microwave radiometer data Type de document : Article/Communication Auteurs : Juha Karvonen, Auteur Année de publication : 2017 Article en page(s) : pp 2871 - 2883 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes descripteurs IGN] analyse comparative [Termes descripteurs IGN] Baltique, mer [Termes descripteurs IGN] épaisseur de la glace [Termes descripteurs IGN] glace de mer [Termes descripteurs IGN] image Aqua-AMSR [Termes descripteurs IGN] image Sentinel-SAR [Termes descripteurs IGN] navigation maritime [Termes descripteurs IGN] Sentinel-1 [Termes descripteurs IGN] télédétection en hyperfréquence Résumé : (Auteur) Sea ice concentration (SIC) is an important sea ice parameter for sea ice navigation, environmental research, and weather and ice forecasting. We have developed and tested a method for estimation of the Baltic Sea SIC using SENTINEL-1 synthetic aperture radar (SAR) and Advanced Microwave Scanning Radiometer 2 passive microwave radiometer (MWR) data. Here, we present the method and results for January 2016. Ice concentration grids of Finnish Meteorological Institute daily ice charts have been used as reference data in this paper. We present a comparison of four SIC estimation methods with our reference data. In addition to the combined SAR/MWR SIC estimation method, we also compare SIC estimates produced using SAR alone and two MWR-based methods. The main target of this paper was to develop and test a high-resolution SIC estimation method suitable for operational use. Numéro de notice : A2017-470 Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern En ligne : http://dx.doi.org/10.1109/TGRS.2017.2655567 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86393 [article]

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)  

Public [article]  inAdvances in space research > vol 58 n° 12 (15 December 2016) . - pp 2617 - 2627 Titre : Is the Jason-2 DORIS oscillator also affected by the South Atlantic Anomaly? Type de document : Article/Communication Auteurs : Pascal Willis , Auteur ; Michael B. Heflin, Auteur ; Bruce J. Haines, Auteur ; Yoaz E. Bar-Sever, Auteur ; Willy I. Bertiger, Auteur ; Mioara Mandea, Auteur Année de publication : 2016 Article en page(s) : pp 2617 - 2627 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes descripteurs IGN] anomalie de Bouguer [Termes descripteurs IGN] Atlantique Sud [Termes descripteurs IGN] co-positionnement [Termes descripteurs IGN] données DORIS [Termes descripteurs IGN] données GPS [Termes descripteurs IGN] erreur systématique [Termes descripteurs IGN] Jason [Termes descripteurs IGN] oscillateur [Termes descripteurs IGN] positionnement ponctuel précis [Termes descripteurs IGN] résidu [Termes descripteurs IGN] série temporelle [Termes descripteurs IGN] station permanente Résumé : (auteur) We analyzed time series of daily DORIS and GPS station coordinate estimates derived from Precise Point Positioning (PPP). The DORIS coordinates were estimated using Jason-2 precise orbits based on GPS data only, implying that the station positions from the two techniques are expressed in the same GPS-based terrestrial reference frame. Comparisons of 3-D vectors of such co-located stations show systematic biases in position around South America when compared to local geodetic ties. We conclude that these results could be explained by a sensitivity of the Jason-2/DORIS oscillator to radiation when the satellite passes over the South Atlantic Anomaly (SAA). The effect for Jason-2 manifests mainly as an offset in station coordinates, though there is also evidence of a drift at the start of the mission that diminishes in time. This contrasts with the experience on Jason-1, wherein large, persistent drifts were observed for stations in this same (SAA) region. The spurious drift is much (∼90%) smaller for Jason-2, which may be attributable to the steps taken prior to launch to harden the oscillator. Analysis of DORIS Doppler residuals may indicate some small degradation after 2009 for these stations. Numéro de notice : A2016--178 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.09.015 date de publication en ligne : 21/09/2016 En ligne : https://doi.org/10.1016/j.asr.2016.09.015 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91806 [article]

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)    

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Lasergrammétrie sous-marine / Yann Morel (2015) 

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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) 

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

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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)  

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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)  

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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)  

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

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A multifrequency polarimetric SAR processing chain to observe oil fields in the Gulf of Mexico / M. Migliaccio in IEEE Transactions on geoscience and remote sensing, vol 49 n° 12 Tome 1 (December 2011)  

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Strapdown INS/DGPS airborne gravimetry tests in the Gulf of Mexico / X. Li in Journal of geodesy, vol 85 n° 9 (September 2011)  

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