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Sea level prediction in the Yellow Sea from satellite altimetry with a combined least squares-neural network approach / Jian Zhao in Marine geodesy, vol 42 n° 4 (July 2019)
[article]
Titre : Sea level prediction in the Yellow Sea from satellite altimetry with a combined least squares-neural network approach Type de document : Article/Communication Auteurs : Jian Zhao, Auteur ; Yanguo Fan, Auteur ; Yuxiang Mu, Auteur Année de publication : 2019 Article en page(s) : pp 344 - 366 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] détection d'anomalie
[Termes IGN] données altimétriques
[Termes IGN] données Jason
[Termes IGN] données Topex-Poseidon
[Termes IGN] image ERS-SAR
[Termes IGN] méthode des moindres carrés
[Termes IGN] montée du niveau de la mer
[Termes IGN] Pacifique nord
[Termes IGN] prévision
[Termes IGN] réseau neuronal artificiel
[Termes IGN] série temporelleRésumé : (auteur) Accessible high-quality observation datasets and proper modeling process are critically required to accurately predict sea level rise in coastal areas. This study focuses on developing and validating a combined least squares-neural network approach applicable to the short-term prediction of sea level variations in the Yellow Sea, where the periodic terms and linear trend of sea level change are fitted and extrapolated using the least squares model, while the prediction of the residual terms is performed by several different types of artificial neural networks. The input and output data used are the sea level anomalies (SLA) time series in the Yellow Sea from 1993 to 2016 derived from ERS-1/2, Topex/Poseidon, Jason-1/2, and Envisat satellite altimetry missions. Tests of different neural network architectures and learning algorithms are performed to assess their applicability for predicting the residuals of SLA time series. Different neural networks satisfactorily provide reliable results and the root mean square errors of the predictions from the proposed combined approach are less than 2 cm and correlation coefficients between the observed and predicted SLA are up to 0.87. Results prove the reliability of the combined least squares-neural network approach on the short-term prediction of sea level variability close to the coast. Numéro de notice : A2019-281 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01490419.2019.1626306 Date de publication en ligne : 12/06/2019 En ligne : https://doi.org/10.1080/01490419.2019.1626306 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93115
in Marine geodesy > vol 42 n° 4 (July 2019) . - pp 344 - 366[article]Reconciling upper mantle seismic velocity and density structure below ocean basins / Isabelle Panet (2019)
Titre : Reconciling upper mantle seismic velocity and density structure below ocean basins Type de document : Article/Communication Auteurs : Isabelle Panet , Auteur ; Barbara Romanowicz, Auteur ; Marianne Greff-Lefftz, Auteur Editeur : Saint-Mandé : Institut national de l'information géographique et forestière - IGN (2012-) Année de publication : 2019 Projets : 1-Pas de projet / Conférence : AGU 2019 Fall Meeting 09/12/2019 13/12/2019 San Francisco Californie - Etats-Unis programme sans actes Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données bathymétriques
[Termes IGN] données GRACE
[Termes IGN] fond marin
[Termes IGN] geoïde marin
[Termes IGN] géophysique interne
[Termes IGN] Indien (océan)
[Termes IGN] manteau terrestre
[Termes IGN] Pacifique (océan)
[Termes IGN] structure géologique
[Termes IGN] vitesse de déplacementRésumé : (auteur) Imaging the spatial pattern of mantle flows and constraining their mass is one of the keys to understand the character of mantle convection inside the Earth, and its interactions with plate motions. The horizontal planform of the flows, their heterogeneity and mass transport at depth, are reflected in variations of the gravity field and seismic velocities, as well as deformations of the Earth's surface. Over ocean basins, these observables show an elusive medium-scale structure. A 1500-2000 km wavelength directional fabric following the present-day absolute plate motion is present in the Pacific Ocean in GRACE satellite gravity data (Hayn et al., 2012), while 2000-km wavelength slow shear velocity anomalies sharing a similar orientation are found in seismic tomography at upper mantle depths below the oceans (SEMUM2, French et al., 2013). Today, the dynamic processes at the origin of these observations remain unresolved.
Here, we develop a joint analysis of satellite gravity and bathymetry data together with the SEMUM2 seismic tomography model, in order to advance our understanding of upper to mid-mantle flows below the oceans. First, we enhance and reconstruct the medium-scale gravity and seafloor topography signals aligned with the present-day plate motion from an analysis of the rates of gravity vector variations and seafloor slopes. Then, we compare the obtained signals with the spatial distribution of shear velocity anomalies at depth. We show that slow velocity anomalies coincide with geoid lows, depressions in the seafloor topography, and mass excess in the mantle, in the Pacific ocean and part of the Indian ocean. We first consider a purely thermal interpretation of the seismic velocity variations, associated with medium-scale convective rolls in the upper to mid-mantle, a process able to only explain the observed geometry of anomalies. Investigating whether the needed mass excess arises from lithospheric or deeper sources, such as at the level of the 660-km interface, we conclude that it lies more likely within the slow velocity anomalies themselves, suggesting hot and dense structures. We finally discuss the possible meaning and implications of these results.Numéro de notice : C2019-058 Affiliation des auteurs : Géodésie+Ext (mi2018-2019) Thématique : POSITIONNEMENT Nature : Poster nature-HAL : Poster-avec-CL DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96896
Titre : Sea surface salinity remote sensing Type de document : Monographie Auteurs : Emmanuel P. Dinnat, Éditeur scientifique ; Xiaobin Yin, Éditeur scientifique Editeur : Bâle [Suisse] : Multidisciplinary Digital Publishing Institute MDPI Année de publication : 2019 Importance : 296 p. Format : 17 x 23 cm ISBN/ISSN/EAN : 978-3-03921-077-0 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] Arctique, océan
[Termes IGN] Atlantique (océan)
[Termes IGN] bande L
[Termes IGN] fusion de données
[Termes IGN] HYbrid Coordinate Ocean Model
[Termes IGN] image SAC-D-Aquarius
[Termes IGN] image SMOS
[Termes IGN] Indien (océan)
[Termes IGN] Méditerranée, mer
[Termes IGN] Mexique (golfe du)
[Termes IGN] modèle de transfert radiatif
[Termes IGN] océanographie
[Termes IGN] Pacifique (océan)
[Termes IGN] salinité
[Termes IGN] Soil Moisture Active Passive
[Termes IGN] surface de la merRésumé : (éditeur) This Special Issue gathers papers reporting research on various aspects of remote sensing of Sea Surface Salinity (SSS) and the use of satellite SSS in oceanography. It includes contributions presenting improvements in empirical or theoretical radiative transfer models; mitigation techniques of external interference such as RFI and land contamination; comparisons and validation of remote sensing products with in situ observations; retrieval techniques for improved coastal SSS monitoring, high latitude SSS and the assessment of ocean interactions with the cryosphere; and data fusion techniques combining SSS with sea surface temperature (SST). New instrument technology for the future of SSS remote sensing is also presented. Note de contenu : 1- Status of Aquarius and salinity continuity
2- The salinity retrieval algorithms for the NASA Aquarius Version 5 and SMAP version3 releases
3- Assessment of Aquarius Sea surface salinity
4- Improving SMOS sea surface salinity in the Western Mediterranean Sea through multivariateand multifractal analysis
5- Seven Years of SMOS sea surface salinity at high latitudes: Variability in Arctic and Sub-Arctic region
6- Inter comparison of in-situ and remote sensing salinity products in the Gulf of Mexico, a river-influenced system
7- Remote sensing of sea surface salinity: Comparison of satellite and in situ observations and impact of retrieval parameters
8- An observational perspective of sea surface salinity in the Southwestern Indian Ocean and its role in the South Asia summer monsoon
9- The potential and challenges of using soil moisture active passive (SMAP) sea surface salinity to monitor Arctic Ocean freshwater changes
10- Assessing coastal SMAP surface salinity accuracy and its application to monitoring Gulf of Maine circulation dynamics
11- SMAP and CalCOFI observe freshening during the 2014–2016 Northeast Pacific warm anomaly
12- Seasonal variability of retroflection structures and transports in the Atlantic Ocean as Inferred from satellite-derived salinity maps
13- Comparison of the retrieval of sea surface salinity using different instrument configurations of MICAP
14- End-to-End simulation of WCOM IMI sea surface salinity retrievalNuméro de notice : 17663 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Recueil / ouvrage collectif DOI : 10.3390/books978-3-03921-077-0 En ligne : https://doi.org/10.3390/books978-3-03921-077-0 Format de la ressource électronique : url Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97393 Assessing the performance of multi-GNSS precise point positioning in Asia-Pacific region / X. Zhao in Survey review, vol 49 n° 354 (September 2017)
[article]
Titre : Assessing the performance of multi-GNSS precise point positioning in Asia-Pacific region Type de document : Article/Communication Auteurs : X. Zhao, Auteur ; S. Wang, Auteur ; C. Liu, Auteur ; J. Ou, Auteur ; X. Yu, Auteur Année de publication : 2017 Article en page(s) : pp 186 - 196 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] Asie (géographie politique)
[Termes IGN] données BeiDou
[Termes IGN] données GLONASS
[Termes IGN] données GPS
[Termes IGN] filtre de Kalman
[Termes IGN] modèle stochastique
[Termes IGN] Pacifique (océan)
[Termes IGN] positionnement ponctuel précis
[Termes IGN] test de performanceRésumé : (Auteur) Multi-Global Navigation Satellite System (GNSS) integration can effectively improve the satellite geometry strength, and certain effect on the precise point positioning (PPP) accuracy and convergence speed. Taking the system difference into account, this paper deduces the unified GNSS observation model, which is extended to the multi-GNSS PPP functional model. Meanwhile, the stochastic model used in Kalman filter parameter estimation is presented in the paper. Furthermore, to evaluate the performance of the multi-GNSS PPP in Asia-Pacific region, observed data from the International GNSS Service reference stations are analysed using the self-developed software. In detail, the results from Global Positioning System (GPS)-, GLObal NAvigation Satellite System (GLONASS)- and BeiDou Navigation Satellite System (BDS)-only PPP, double combined PPP and GPS/GLONASS/BDS combined PPP under the different observation duration and cut-off elevation angles are analysed. Results demonstrate: (1) compared with the single system PPP, the convergence speed of the multi-GNSS PPP is improved while the accuracy is not significantly improved after processing the 24-h data set; (2) when the observation duration is short, such as 0.5 h, the mean convergence percentage of the BDS combined with GPS and GLONASS PPP increases by an average of 49.6% compared with the single individual systems except for BDS, respectively, under the cut-off angle of 5° and (3) when PPP positioning with high cut-off elevation angles, and at the point of centimetre-level positioning, the GPS/GLONASS/BDS combined PPP has a better performance on the convergence percentage and convergence speed. For example, the percentages of the position biases within 0–5 cm for GPS/GLONASS/BDS are increased by 7.2 and 4.5% in North and East direction compared with GPS/GLONASS under the cut-off angle of 35°, more than any other. And the mean convergence time is only 14.5 min. Numéro de notice : A2017-544 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2016.1151576 En ligne : https://doi.org/10.1080/00396265.2016.1151576 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86599
in Survey review > vol 49 n° 354 (September 2017) . - pp 186 - 196[article]Marine terraces and rates of vertical tectonic motion: The importance of glacio-isostatic adjustment along the Pacific coast of central North America / Alexander R. Simms in GSA bulletin, vol 128 n° 1-2 ([01/01/2016])
[article]
Titre : Marine terraces and rates of vertical tectonic motion: The importance of glacio-isostatic adjustment along the Pacific coast of central North America Type de document : Article/Communication Auteurs : Alexander R. Simms, Auteur ; Hélène Rouby , Auteur ; Kurt Lambeck, Auteur Année de publication : 2016 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Amérique du nord
[Termes IGN] déformation verticale de la croute terrestre
[Termes IGN] fond marin
[Termes IGN] littoral
[Termes IGN] niveau de la mer
[Termes IGN] Pacifique nord
[Termes IGN] rebond post-glaciaire
[Termes IGN] tectonique des plaquesRésumé : (auteur) Differences in marine terrace elevations across the Pacific coast of North America have long been assumed to be a result of differences in the rates of tectonic motion. However, other processes, particularly glacio-isostatic adjustment, lead to regional variations in sea levels. In this study, we compiled the elevations of marine isotope stage (MIS) 5e (ca. 119–129 ka), 5c (ca. 106 ka), and 5a (ca. 84 ka) terraces across the Pacific coast of central North America and compared these regional variations in elevation with model predictions of glacio-isostatic adjustment after correcting for tectonics. These predictions are generally consistent with the observed trends in the elevations of the terraces and show that this process created up to 20 m of coeval variation in local sea levels along the Pacific coast of central North America (between 20°N and 45°N) during MIS 5c and MIS 5a, but less, ∼4 m, during MIS 5e. Accounting for glacio-isostatic adjustment reduces the variability in uplift rates calculated at individual locations using different-aged terraces as datums. Ignoring glacio-isostatic adjustment leads to overestimated uplift rates by an average of 40%, but up to 72%, across the Pacific coast of central North America. An understanding of regional variations in glacio-isostatic adjustment–corrected sea levels also contributes to the correct identification of marine terraces with mistaken ages. Numéro de notice : A2016--188 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1130/B31299.1 Date de publication en ligne : 29/06/2015 En ligne : https://doi.org/10.1130/B31299.1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91830
in GSA bulletin > vol 128 n° 1-2 [01/01/2016][article]Recent variations of supraglacial lakes on the Baltoro Glacier in the central Karakoram Himalaya and its possible teleconnections with the pacific decadal oscillation / Bijeesh Kozhikkodan Veettil in Geocarto international, vol 31 n° 1 - 2 (January - February 2016)PermalinkDisplacement and maintenance of control points at Okinotorishima Island on Philippine Sea / Yudai Sato in Bulletin of the GeoSpatial Information authority of Japan, vol 62 (December 2014)PermalinkOceanwide precise determination of sea surface height from in-situ measurements on cargo ships / Ole Roggenbuck in Marine geodesy, vol 37 n° 1 (March - May 2014)PermalinkThe stability of tide gauges in the south Pacific determined from multiepoch geodetic levelling, 1992 to 2010 / Manoj Nilesh Deo in Marine geodesy, vol 36 n° 3 (September - November 2013)PermalinkQuelles frontières en mer de Chine méridionale ? / Cécile Marin in Carto, le monde en cartes, n° 17 (mai - juin 2013)PermalinkWavelet‐based directional analysis of the gravity field : evidence for large‐scale undulations / M. Hayn in Geophysical journal international, vol 189 n° 3 (June 2012)PermalinkEffect of climatic cycles in Pacific Ocean on mean sea level variations over the Southwest Pacific Ocean and Tasman Sea / Anthony Wiart (2012)PermalinkPacific geoid anomalies revisited in light of thermochemical oscillating domes in the lower mantle / Cécilia Cadio in Earth and planetary science letters, vol 306 n° 1-2 (June 2011)PermalinkAbsolute seafloor vertical positioning using combined pressure gauge and kinematic GPS data / Valérie Ballu in Journal of geodesy, vol 84 n° 1 (January 2010)PermalinkPotential volcanological applications of the DORIS system. A geodetic study of the Socorro Island (Mexico) coordinate time-series / Pierre Briole in Geophysical journal international, vol 178 n° 1 (July 2009)Permalink