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Auteur John Wahr |
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Revisiting the pole tide for and from satellite altimetry / Shailen Desai in Journal of geodesy, vol 89 n° 12 (december 2015)
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Titre : Revisiting the pole tide for and from satellite altimetry Type de document : Article/Communication Auteurs : Shailen Desai, Auteur ; John Wahr, Auteur Année de publication : 2015 Article en page(s) : pp 1233 - 1243 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] altimètre
[Termes IGN] altimétrie satellitaire par radar
[Termes IGN] analyse diachronique
[Termes IGN] géocentre
[Termes IGN] marée terrestre
[Termes IGN] masse d'eau
[Termes IGN] masse de la Terre
[Termes IGN] mouvement du pôle
[Termes IGN] surcharge océaniqueRésumé : (auteur) Satellite altimeter sea surface height observations include the geocentric displacements caused by the pole tide, namely the response of the solid Earth and oceans to polar motion. Most users of these data remove these effects using a model that was developed more than 20 years ago. We describe two improvements to the pole tide model for satellite altimeter measurements. Firstly, we recommend an approach that improves the model for the response of the oceans by including the effects of self-gravitation, loading, and mass conservation. Our recommended approach also specifically includes the previously ignored displacement of the solid Earth due to the load of the ocean response, and includes the effects of geocenter motion. Altogether, this improvement amplifies the modeled geocentric pole tide by 15 %, or up to 2 mm of sea surface height displacement. We validate this improvement using two decades of satellite altimeter measurements. Secondly, we recommend that the altimetry pole tide model exclude geocentric sea surface displacements resulting from the long-term drift in polar motion. The response to this particular component of polar motion requires a more rigorous approach than is used by conventional models. We show that erroneously including the response to this component of polar motion in the pole tide model impacts interpretation of regional sea level rise by ±0.25 mm/year. Numéro de notice : A2015-888 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0848-7 Date de publication en ligne : 27/08/2020 En ligne : https://doi.org/10.1007/s00190-015-0848-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79436
in Journal of geodesy > vol 89 n° 12 (december 2015) . - pp 1233 - 1243[article]Estimating geoid height change in North America: past, present and future / T. Jacob in Journal of geodesy, vol 86 n° 5 (May 2012)
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Titre : Estimating geoid height change in North America: past, present and future Type de document : Article/Communication Auteurs : T. Jacob, Auteur ; John Wahr, Auteur ; R. Gross, Auteur ; S. Swenson, Auteur ; A. Geruo, Auteur Année de publication : 2012 Article en page(s) : pp 337 - 358 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Amérique du nord
[Termes IGN] champ de pesanteur local
[Termes IGN] données GRACE
[Termes IGN] éruption volcanique
[Termes IGN] Etats-Unis
[Termes IGN] géoïde gravimétrique
[Termes IGN] géoïde local
[Termes IGN] surveillance géologiqueRésumé : (Auteur) The forthcoming GRAV-D gravimetric geoid model over the United States is to be updated regularly to account for changes in geoid height. Its baseline precision is to be at the 10–20 mm level over non-mountainous regions. The aim of this study is to provide an estimate of the magnitude, time scale, and spatial footprint of geoid height change over North America, from mass redistribution processes of hydrologic, cryospheric and solid Earth nature. Geoid height changes from continental water storage changes over the past 50 years and predicted over the next century are evaluated and are highly dependent on the used model. Groundwater depletion from anthropogenic pumping in regional scale aquifers may lead to geoid changes of 10 mm magnitude every 50–100 years. The GRACE time varying gravity fields are used to (I) assess the errors in a glacial isostatic adjustment model, which, if used to correct the GRAV-D model, may induce errors at the 10 mm geoid height level after ~20 years, (II), evaluate geoid height change over ice mass loss regions of North America, which, if they remain unchanged in the future, may lead to geoid height changes at the 10 mm level in under a decade and (III), compute sea level rise and its effect on the geoid, which is found to be negligible. Coseismic gravitational changes from past North American earthquakes are evaluated, and lead to geoid change at the 10-mm level for only the largest thrust earthquakes. Finally, geoid change from volcanic processes are assessed and found to be significant with respect to the GRAV-D geoid model baseline precision for cataclysmic events, such as that of the 1980 Mt. St. Helens eruption. Recommendations on how to best monitor geoid change in the future are given. Numéro de notice : A2012-242 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0522-7 Date de publication en ligne : 01/11/2011 En ligne : https://doi.org/10.1007/s00190-011-0522-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31688
in Journal of geodesy > vol 86 n° 5 (May 2012) . - pp 337 - 358[article]Exemplaires(1)
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