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Spherical harmonic synthesis of area-mean potential values on irregular surfaces / Blažej Bucha in Journal of geodesy, vol 96 n° 10 (October 2022)
[article]
Titre : Spherical harmonic synthesis of area-mean potential values on irregular surfaces Type de document : Article/Communication Auteurs : Blažej Bucha, Auteur Année de publication : 2022 Article en page(s) : n° 68 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de gravitation
[Termes IGN] convergence
[Termes IGN] harmonique sphérique
[Termes IGN] surface hétérogène
[Termes IGN] transformation de Legendre
[Termes IGN] transformation rapide de FourierRésumé : (auteur) We present a method to integrate external solid spherical harmonic expansions at geographical grids residing on undulated surfaces. It can be used to evaluate area-mean potential values on planetary surfaces that vary within grid cells. This is in contrast with available methods, which assume cells with a constant spherical radius only. When formulating the technique, we took advantage of 2D spherical Fourier methods to improve the computational speed. The price to be paid are high memory requirements, even with moderate maximum harmonic degrees such as 100 (both of the potential and of the irregular surface). In numerical experiments, we validate the method against independent area-mean potential values to prove its correctness. A study of the series behavior below the sphere of convergence shows that the series may diverge on planetary topographies, similarly as it is with its point-value counterpart. The method can be utilized in numerical studies of the change of boundary method, one of the pivotal concepts of recent high-degree models such as EGM2008. A numerical implementation is made available through CHarm, a C library to work with spherical harmonics up to high degrees. CHarm is accessible via https://github.com/blazej-bucha/charm. Numéro de notice : A2022-736 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-022-01658-1 Date de publication en ligne : 27/09/2022 En ligne : https://doi.org/10.1007/s00190-022-01658-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101708
in Journal of geodesy > vol 96 n° 10 (October 2022) . - n° 68[article]The use of gravity data to determine orthometric heights at the Hong Kong territories / Albertini Nsiah Ababio in Journal of applied geodesy, vol 16 n° 4 (October 2022)
[article]
Titre : The use of gravity data to determine orthometric heights at the Hong Kong territories Type de document : Article/Communication Auteurs : Albertini Nsiah Ababio, Auteur ; Robert Tenzer, Auteur Année de publication : 2022 Article en page(s) : pp 401 - 416 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] altitude orthométrique
[Termes IGN] correction orthométrique
[Termes IGN] Hong-Kong
[Termes IGN] interpolation
[Termes IGN] levé gravimétrique
[Termes IGN] montagne
[Termes IGN] système de référence local
[Vedettes matières IGN] AltimétrieRésumé : (auteur) The Hong Kong Principal Datum (HKPD) is the currently adopted official geodetic vertical datum at the Hong Kong territories. The HKPD is practically realized by heights of levelling benchmarks. The HKPD heights are, however, neither normal nor orthometric. The reason is that heights of levelling benchmarks were determined from precise levelling measurements, but without involving gravity observations along levelling lines. To reduce systematic errors due to disregarding the gravity information along levelling lines, we used terrestrial and marine gravity data to interpolate gravity values at levelling benchmarks in order to compute and apply the orthometric correction to measured levelling height differences. Our results demonstrate the importance of incorporating the gravity information even for a relatively small region but characterized by a rough topography with heights of levelling benchmarks exceeding several hundreds of meters. According to our estimates, the orthometric correction reaches (and even slightly exceeds) ±2 cm, with maxima along levelling lines crossing mountain chains. Numéro de notice : A2022-742 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2022-0012 Date de publication en ligne : 04/08/2022 En ligne : https://doi.org/10.1515/jag-2022-0012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101724
in Journal of applied geodesy > vol 16 n° 4 (October 2022) . - pp 401 - 416[article]Dense mantle flows periodically spaced below ocean basins / Isabelle Panet in Earth and planetary science letters, vol 594 (15 September 2022)
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Titre : Dense mantle flows periodically spaced below ocean basins Type de document : Article/Communication Auteurs : Isabelle Panet , Auteur ; Marianne Greff-Lefftz, Auteur ; Barbara Romanowicz, Auteur Année de publication : 2022 Projets : Université de Paris / Clerici, Christine Article en page(s) : n° 117745 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] convection
[Termes IGN] déformation de la croute terrestre
[Termes IGN] dynamique des fluides
[Termes IGN] fond marin
[Termes IGN] Indien (océan)
[Termes IGN] lithosphère
[Termes IGN] manteau terrestre
[Termes IGN] Pacifique (océan)Résumé : (auteur) Understanding mantle flow is key to elucidate how deep Earth dynamics relate to tectonics at the global scale. The convective mass transport is reflected in lateral variations of the gravity field, seismic velocities, as well as deformations of the Earth's surface. Yet, upper to mid-mantle dynamics have been difficult to constrain at the medium scales of thousands of km. Here, we analyze the second-order horizontal derivatives of seafloor topography and of the gravity potential over the Pacific and Northern Indian ocean basins, and provide evidence for periodic undulations of 1600-2000 km wavelength in both signals, elongated along the direction of absolute plate motion. We investigate potential crustal and lithospheric sources and show that at least part of this signal must originate below the lithosphere, with alignments of sub-lithospheric upper mantle mass excess below seafloor lows. Furthermore, we find that these alignments coincide geographically over wide areas with similarly periodic slow seismic velocity fingers located at upper mantle depths. These two fields may thus record an intermediate scale of mantle convection below ocean basins, which cannot be explained by purely thermal convection and requires instead lateral variations in composition in the upper mantle. Elucidating the nature of the detected mass excess sources coincident with the slow seismic velocities calls for a joint dynamical modeling of all observations in a thermo-chemical context. Numéro de notice : A2022-692 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.epsl.2022.117745 En ligne : https://doi.org/10.1016/j.epsl.2022.117745 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101809
in Earth and planetary science letters > vol 594 (15 September 2022) . - n° 117745[article]Deflection of vertical effect on direct georeferencing in aerial mobile mapping systems: A case study in Sweden / Mohammad Bagherbandi in Photogrammetric record, vol 37 n° 179 (September 2022)
[article]
Titre : Deflection of vertical effect on direct georeferencing in aerial mobile mapping systems: A case study in Sweden Type de document : Article/Communication Auteurs : Mohammad Bagherbandi, Auteur ; Arash Jouybari, Auteur ; Faramarz Nilfouroushan, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 285 - 305 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie
[Termes IGN] couplage GNSS-INS
[Termes IGN] déviation de la verticale
[Termes IGN] Earth Gravity Model 2008
[Termes IGN] ellipsoïde de référence
[Termes IGN] géoréférencement direct
[Termes IGN] photogrammétrie aérienne
[Termes IGN] quasi-géoïde
[Termes IGN] Suède
[Termes IGN] système de numérisation mobileRésumé : (auteur) GNSS/INS applications are being developed, especially for direct georeferencing in airborne photogrammetry. Achieving accurately georeferenced products from the integration of GNSS and INS requires removing systematic errors in the mobile mapping systems. The INS sensor's uncertainty is decreasing; therefore, the influence of the deflection of verticals (DOV, the angle between the plumb line and normal to the ellipsoid) should be considered in the direct georeferencing. Otherwise, an error is imposed for calculating the exterior orientation parameters of the aerial images and aerial laser scanning. This study determines the DOV using the EGM2008 model and gravity data in Sweden. The impact of the DOVs on horizontal and vertical coordinates, considering different flight altitudes and camera field of view, is assessed. The results confirm that the calculated DOV components using the EGM2008 model are sufficiently accurate for aerial mapping system purposes except for mountainous areas because the topographic signal is not modelled correctly. Numéro de notice : A2022-937 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : 10.1111/phor.12421 Date de publication en ligne : 25/07/2022 En ligne : https://doi.org/10.1111/phor.12421 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102683
in Photogrammetric record > vol 37 n° 179 (September 2022) . - pp 285 - 305[article]A high-resolution gravimetric geoid model for Kingdom of Saudi Arabia / Ahmed Zaki in Survey review, vol 54 n° 386 (September 2022)
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Titre : A high-resolution gravimetric geoid model for Kingdom of Saudi Arabia Type de document : Article/Communication Auteurs : Ahmed Zaki, Auteur ; Saad Mogren, Auteur Année de publication : 2022 Article en page(s) : pp 375 - 390 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Arabie Saoudite
[Termes IGN] géoïde altimétrique
[Termes IGN] géoïde gravimétrique
[Termes IGN] geoïde marin
[Termes IGN] intégrale de Stokes
[Termes IGN] modèle de géopotentiel
[Termes IGN] modèle numérique de surface
[Termes IGN] nivellement avec assistance GPS
[Termes IGN] transformation rapide de FourierRésumé : (auteur) A high-resolution gravimetric geoid model for the Kingdom of Saudi Arabia area was determined. A data set of 459,848 land gravity, 80,632 shipborne marine gravity data, DTU17 altimetry gravity model, and XGM2019e global geopotential model. The computation strategy followed for modelling of the gravimetric geoid is based on the Remove-Compute-Restore with Residual Terrain Model reduction and the 1D- Fast Fourier Transform approach technique. The geoid heights have been determined by using the Stokes integral with Wong–Gore modification. The accuracy of the resulting geoid models was evaluated by comparing them with 5385 GPS/levelling points. The geoid accuracy over all the kingdom is better than 11 cm in STD sense and the comparison in sub-areas obtained accuracy range from 2.8 to 11.9 cm according to the density of gravity observations. Numéro de notice : A2022-657 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2021.1944544 Date de publication en ligne : 29/06/2021 En ligne : https://doi.org/10.1080/00396265.2021.1944544 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101508
in Survey review > vol 54 n° 386 (September 2022) . - pp 375 - 390[article]Impact assessment of the seasonal hydrological loading on geodetic movement and seismicity in Nepal Himalaya using GRACE and GNSS measurements / Devendra Shashikant Nagale in Geodesy and Geodynamics, vol 13 n° 5 (September 2022)PermalinkMICROSCOPE Mission: Final Results of the Test of the Equivalence Principle / Pierre Touboul in Physical Review Letters, vol 129 n° 12 ([01/09/2022])PermalinkValidation and comparison of several global geopotential models with an official quasigeoid solution of Serbia / Marko D. Stanković in Geodetski vestnik, vol 66 n° 3 (September - November 2022)PermalinkEfficient calculation of distance transform on discrete global grid systems / Meysam Kazemi in ISPRS International journal of geo-information, vol 11 n° 6 (June 2022)PermalinkPermalinkComparison between Gaussian and decorrelation filters of GRACE-based RL05 temporal gravity solutions over Egypt / Basem Elsaka in Survey review, vol 54 n° 384 (May 2022)PermalinkModeling gravimetric signatures of third-degree ocean tides and their detection in superconducting gravimeter records / Roman Sulzbach in Journal of geodesy, vol 96 n° 5 (May 2022)PermalinkDeep mass redistribution prior to the 2010 Mw 8.8 Maule (Chile) Earthquake revealed by GRACE satellite gravity / Marie Bouih in Earth and planetary science letters, vol 584 (15 April 2022)PermalinkQuantifying discrepancies in the three-dimensional seasonal variations between IGS station positions and load models / Yujiao Niu in Journal of geodesy, vol 96 n° 4 (April 2022)PermalinkEstimation of the height datum geopotential value of Hong Kong using the combined Global Geopotential Models and GNSS/levelling data / Panpan Zhang in Survey review, vol 54 n° 383 (March 2022)Permalink