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A generalized theory of the figure of the Earth : formulae / Chengli Huang in Journal of geodesy, vol 93 n° 3 (March 2019)
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Titre : A generalized theory of the figure of the Earth : formulae Type de document : Article/Communication Auteurs : Chengli Huang, Auteur ; Yu Liu, Auteur ; Chenjun Liu, Auteur ; Mian Zhang, Auteur Année de publication : 2019 Article en page(s) : pp 297 - 317 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie
[Termes descripteurs IGN] croute terrestre
[Termes descripteurs IGN] ellipticité (géométrie)
[Termes descripteurs IGN] équation de Clairaut
[Termes descripteurs IGN] figure de la Terre
[Termes descripteurs IGN] surface de référenceRésumé : (Auteur) Traditionally a laterally homogeneous and spherical base Earth model (e.g., the PREM model) is considered as input when computing the Earth’s equipotential surfaces, which are then resulted to be in symmetric shape. However, the Earth, known with a complex distribution of interior material and density, especially in the upper mantle and the crust, cannot be treated as a symmetric sphere. Recently, a CRUST1.0 model of crust layer is published and well accepted. But the effect caused by the asymmetric crust (and mantle) on equilibrium figures of the Earth cannot be analyzed by the traditional theories. A generalized theory of the figure of the Earth to third-order precision is firstly proposed in this paper, as well as the iterative calculation strategy to solve the complex equation system. In order to validate this generalized theory, the degeneration of this generalized theory with the PREM model is made and is compared with traditional theories, and it is shown that the result of this generalized theory, after degeneration, is consistent very well with traditional theory. Meanwhile, the effect (including both the direct and indirect effects) of the crust layer, from the CRUST1.0 model, on the figures of equipotential surfaces of the Earth’s interior, as well as their effects on the global dynamics flattening, will be presented as an application of this theory in accompanying paper. Numéro de notice : A2019-150 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1159-6 date de publication en ligne : 15/06/2018 En ligne : https://doi.org/10.1007/s00190-018-1159-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92488
in Journal of geodesy > vol 93 n° 3 (March 2019) . - pp 297 - 317[article]
Titre : Linear Algebra : A Course for Physicists and Engineers Type de document : Monographie Auteurs : Arak M. Mathai, Auteur ; Hans J. Haubold, Auteur Editeur : Berlin, New York : Walter de Gruyter Année de publication : 2017 Importance : 450 p. Format : 17 x 24 cm ISBN/ISSN/EAN : 978-3-11-056235-4 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Algèbre
[Termes descripteurs IGN] algèbre linéaire
[Termes descripteurs IGN] arc
[Termes descripteurs IGN] équation différentielle
[Termes descripteurs IGN] espace vectoriel
[Termes descripteurs IGN] matrice
[Termes descripteurs IGN] optimisation (mathématiques)
[Termes descripteurs IGN] statistique mathématiqueRésumé : (éditeur) In order not to intimidate students by a too abstract approach, this textbook on linear algebra is written to be easy to digest by non-mathematicians. It introduces the concepts of vector spaces and mappings between them without dwelling on statements such as theorems and proofs too much. It is also designed to be self-contained, so no other material is required for an understanding of the topics covered. As the basis for courses on space and atmospheric science, remote sensing, geographic information systems, meteorology, climate and satellite communications at UN-affiliated regional centers, various applications of the formal theory are discussed as well. These include differential equations, statistics, optimization and some engineering-motivated problems in physics. Note de contenu : 1- Vectors
2- Matrices
3- Determinants
4- Eigenvalues and eigenvectors
5- Somme applications of matrices and determinants
6- Matrix series and additional properties of matricesNuméro de notice : 25804 Affiliation des auteurs : non IGN Thématique : MATHEMATIQUE Nature : Monographie DOI : 10.1515/9783110562507 En ligne : https://doi.org/10.1515/9783110562507 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96609
Titre : Introduction to partial differential equations Type de document : Guide/Manuel Auteurs : David Borthwick, Auteur Editeur : Springer International Publishing Année de publication : 2016 Importance : 636 p. Format : 18 x 26 cm ISBN/ISSN/EAN : 978-3-319-48936-0 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Mathématique
[Termes descripteurs IGN] équation de Laplace
[Termes descripteurs IGN] équation différentielle
[Termes descripteurs IGN] équation linéaire
[Termes descripteurs IGN] onde acoustique
[Termes descripteurs IGN] série de Fourier
[Termes descripteurs IGN] transformation de FourierRésumé : (éditeur) This textbook is designed for a one year course covering the fundamentals of partial differential equations, geared towards advanced undergraduates and beginning graduate students in mathematics, science, engineering, and elsewhere. The exposition carefully balances solution techniques, mathematical rigor, and significant applications, all illustrated by numerous examples. Extensive exercise sets appear at the end of almost every subsection, and include straightforward computational problems to develop and reinforce new techniques and results, details on theoretical developments and proofs, challenging projects both computational and conceptual, and supplementary material that motivates the student to delve further into the subject.
No previous experience with the subject of partial differential equations or Fourier theory is assumed, the main prerequisites being undergraduate calculus, both one- and multi-variable, ordinary differential equations, and basic linear algebra. While the classical topics of separation of variables, Fourier analysis, boundary value problems, Green's functions, and special functions continue to form the core of an introductory course, the inclusion of nonlinear equations, shock wave dynamics, symmetry and similarity, the Maximum Principle, financial models, dispersion and solitons, Huygens'. Principle, quantum mechanical systems, and more make this text well attuned to recent developments and trends in this active field of contemporary research. Numerical approximation schemes are an important component of any introductory course, and the text covers the two most basic approaches: finite differences and finite elements.Note de contenu : 1- Introduction
2- Preliminaries
3- Conservation Equations and Characteristics
4- The Wave Equation
5- Separation of Variables
6- The Heat Equation
7- Function Spaces
8- Fourier Series
9- Maximum Principles
10- Weak Solutions
11- Variational Methods
12- Distributions
13- The Fourier TransformNuméro de notice : 25868 Affiliation des auteurs : non IGN Thématique : MATHEMATIQUE Nature : Manuel DOI : 10.1007/978-3-319-48936-0 En ligne : https://doi.org/10.1007/978-3-319-48936-0 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95528 A synergy method to improve ensemble weather predictions and differential SAR interferograms / Franz-Georg Ulmer in ISPRS Journal of photogrammetry and remote sensing, vol 109 (November 2015)
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Titre : A synergy method to improve ensemble weather predictions and differential SAR interferograms Type de document : Article/Communication Auteurs : Franz-Georg Ulmer, Auteur ; Nico Adam, Auteur Année de publication : 2015 Article en page(s) : pp 98 - 107 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes descripteurs IGN] algorithme
[Termes descripteurs IGN] correction différentielle
[Termes descripteurs IGN] effet atmosphérique
[Termes descripteurs IGN] équation différentielle
[Termes descripteurs IGN] image radar moirée
[Termes descripteurs IGN] interferométrie différentielle
[Termes descripteurs IGN] interféromètrie par radar à antenne synthétique
[Termes descripteurs IGN] Pays-Bas
[Termes descripteurs IGN] prévision météorologiqueRésumé : (auteur) A compensation of atmospheric effects is essential for mm-sensitivity in differential interferometric synthetic aperture radar (DInSAR) techniques. Numerical weather predictions are used to compensate these disturbances allowing a reduction in the number of required radar scenes. Practically, predictions are solutions of partial differential equations which never can be precise due to model or initialisation uncertainties. In order to deal with the chaotic nature of the solutions, ensembles of predictions are computed. From a stochastic point of view, the ensemble mean is the expected prediction, if all ensemble members are equally likely. This corresponds to the typical assumption that all ensemble members are physically correct solutions of the set of partial differential equations. DInSAR allows adding to this knowledge. Observations of refractivity can now be utilised to check the likelihood of a solution and to weight the respective ensemble member to estimate a better expected prediction.
The objective of the paper is to show the synergy between ensemble weather predictions and differential interferometric atmospheric correction. We demonstrate a new method first to compensate better for the atmospheric effect in DInSAR and second to estimate an improved numerical weather prediction (NWP) ensemble mean. Practically, a least squares fit of predicted atmospheric effects with respect to a differential interferogram is computed. The coefficients of this fit are interpreted as likelihoods and used as weights for the weighted ensemble mean. Finally, the derived weighted prediction has minimal expected quadratic errors which is a better solution compared to the straightforward best-fitting ensemble member. Furthermore, we propose an extension of the algorithm which avoids the systematic bias caused by deformations. It makes this technique suitable for time series analysis, e.g. persistent scatterer interferometry (PSI). We validate the algorithm using the well known Netherlands-DInSAR test case and first show that the atmospheric compensation improves by nearly 40% compared to the straightforward technique. Second, we compare our results with independent sea level pressure data. In our test case, the mean squared error is reduced by 29% compared to the averaged ensemble members with equal weights. An application demonstration using actual Sentinel-1 data and a typical test site with significant subsidence (Mexico City) completes the paper.Numéro de notice : A2015-858 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2015.09.004 date de publication en ligne : 29/09/2015 En ligne : https://doi.org/10.1016/j.isprsjprs.2015.09.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79240
in ISPRS Journal of photogrammetry and remote sensing > vol 109 (November 2015) . - pp 98 - 107[article]
Titre : Les lignes géodésiques d'un tore Type de document : Guide/Manuel Auteurs : Abdelmajid Ben Hadj Salem, Auteur Editeur : Tunis [Tunisie] : Ministère de l’Equipement et de l’Environnement Année de publication : 2015 Autre Editeur : Tunis : Office de la Topographie et de la Cartographie OTC Importance : 6 p. Note générale : bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Géodésie
[Termes descripteurs IGN] équation différentielle
[Termes descripteurs IGN] ligne géodésique
[Termes descripteurs IGN] résolution de problème
[Termes descripteurs IGN] toreRésumé : (auteur)[Introduction] Dans cet article, nous proposons d’écrire les équations des géodésiques d'un tore, et de les résoudre. Note de contenu : 1. Introduction
2. Les équations différentielles des lignes géodésiques
3. Résolution du problème dans le cas généralNuméro de notice : 19753 Affiliation des auteurs : non IGN Thématique : MATHEMATIQUE/POSITIONNEMENT Nature : Manuel de cours Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84552 Documents numériques
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