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An improved empirical model for the effect of long-period ocean tides on polar motion / Richard S. Gross in Journal of geodesy, vol 83 n° 7 (July 2009)  

Public [article]  inJournal of geodesy > vol 83 n° 7 (July 2009) . - pp 635 - 644 Titre : An improved empirical model for the effect of long-period ocean tides on polar motion Type de document : Article/Communication Auteurs : Richard S. Gross, Auteur Année de publication : 2009 Article en page(s) : pp 635 - 644 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] analyse diachronique [Termes IGN] axe de rotation de la Terre [Termes IGN] marée océanique [Termes IGN] modèle dynamique [Termes IGN] moment cinétique atmosphérique [Termes IGN] moment cinétique océanique [Termes IGN] mouvement du pôle Résumé : (Auteur) Because the tide-raising potential is symmetric about the Earth’s polar axis it can excite polar motion only by acting upon non-axisymmetric features of the Earth like the oceans. In fact, after removing atmospheric and non-tidal oceanic effects, polar motion excitation observations show a strong fortnightly tidal signal that is not completely explained by existing dynamical and empirical ocean tide models. So a new empirical model for the effect of the termensual (Mtm and mtm), fortnightly (Mf and mf), and monthly (Mm) tides on polar motion is derived here by fitting periodic terms at these tidal frequencies to polar motion excitation observations that span 2 January 1980 to 8 September 2006 and from which atmospheric and non-tidal oceanic effects have been removed. While this new empirical tide model can fully explain the observed fortnightly polar motion excitation signal during this time interval it would still be desirable to have a model for the effect of long-period ocean tides on polar motion that is determined from a dynamical ocean tide model and that is therefore independent of polar motion observations. Copyright Springer Numéro de notice : A2009-303 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-008-0277-y Date de publication en ligne : 28/10/2008 En ligne : https://doi.org/10.1007/s00190-008-0277-y Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29933 [article]

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Singularity free formulations of the geodetic boundary value problem in gravity-space / G. Austen in Journal of geodesy, vol 83 n° 7 (July 2009)  

Public [article]  inJournal of geodesy > vol 83 n° 7 (July 2009) . - pp 645 - 657 Titre : Singularity free formulations of the geodetic boundary value problem in gravity-space Type de document : Article/Communication Auteurs : G. Austen, Auteur ; W. Keller, Auteur Année de publication : 2009 Article en page(s) : pp 645 - 657 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] équation différentielle [Termes IGN] équation non linéaire [Termes IGN] force de gravitation [Termes IGN] problème des valeurs limites [Termes IGN] simulation numérique [Termes IGN] valeur limite Résumé : (Auteur) The idea of transforming the geodetic boundary value problem into a boundary value problem with a fixed boundary dates back to the 1970s of the last century. This transformation was found by F. Sanso and was named as gravity-space transformation. Unfortunately, the advantage of having a fixed boundary for the transformed problem was counterbalanced by the theoretical as well as practical disadvantage of a singularity at the origin. In the present paper two more versions of a gravity-space transformation are investigated, where none of them has a singularity. In both cases the transformed differential equations are nonlinear. Therefore, a special emphasis is laid on the linearized problems and their relationships to the simple Hotine-problem and to the symmetries between both formulations. Finally, in numerical simulation study the accuracy of the solutions of both linearized problems is studied and factors limiting this accuracy are identified. Copyright Springer Numéro de notice : A2009-304 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-008-0278-x En ligne : https://doi.org/10.1007/s00190-008-0278-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29934 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-09061	SL	Revue	Centre de documentation	Revues en salle	Disponible