A revised value of the Earth’s dynamical ellipticity
| Autor: | Escapa, A., Baenas, T., Ferrandiz, J. |
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| Rok vydání: | 2023 |
| Zdroj: | XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
| DOI: | 10.57757/iugg23-2626 |
| Popis: | The Earth’s dynamical ellipticity H=(C-A)/C —where C is the polar principal moment of inertia and A the mean equatorial one— is a key parameter both for the precession-nutation theory and also as a fundamental standard. Indeed, first order precession-nutation formulae are proportional to it and its value is among the IERS numerical standards (IERS Conventions 2010). Moreover, from the point of view of Geodesy, H is the only parameter which enables to derive the principal moment of inertia C (Bursa, 1995).We revise the current value given in IAU2006/2000 precession-nutation model (Capitaine et al., 2003), obtained from the precession model. In particular, following Escapa et al. (2022), we focus on: (1) the updating of the lunisolar second-order contribution in the sense of perturbation theories; (2) the incorporation of all the contributions due to the Earth non-rigidity that stem from the tidal redistribution of mass; and, for the first time, (3) the adoption of a tidal system in use with H, providing its value in the zero-frequency convention.In this way, the resulting value is updated to the last precession-nutation models (Baenas et al. 2017, 2020) and follows IAG resolutions about the use of tidal systems (Res. 161, GA XVIII, 1983). The relative changes with respect to the present numerical standard of H are about 6 ppm, on the assumption that the current value was given in the same tidal system. The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) |
| Databáze: | OpenAIRE |
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