1. Length-of-day and space-geodetic determination of the Earth's variable gravity field
- Author
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G. Bourda, Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Gravity (chemistry) ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,010504 meteorology & atmospheric sciences ,Satellite laser ranging ,Geodetic datum ,International Earth Rotation and Reference Systems Service ,Geophysics ,Moment of inertia ,010502 geochemistry & geophysics ,Geodesy ,Rotation ,01 natural sciences ,Physics::Geophysics ,[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] ,Gravitational field ,13. Climate action ,Geochemistry and Petrology ,Physics::Space Physics ,Computers in Earth Sciences ,Geology ,0105 earth and related environmental sciences ,Earth's rotation - Abstract
International audience; The temporal variations of the Earth?s gravity field, nowadays routinely determined from satellite laser ranging (SLR) and GRACE (Gravity Recovery And Climate Experiment), are related to changes in the Earth?s rotation rate through the Earth?s inertia tensor. We study this connection from actual data by comparing the traditional length-of-day (LOD) measurements provided by the International Earth Rotation and Reference Systems Service (IERS) to the variations of the degree-2 and order-0 Stokes coefficient of the gravity field determined from fitting the orbits of the LAGEOS-1 and ?2 satellites since 1985. The two series show a good correlation (0.62) and similar annual and semi-annual signals, indicating that the gravity-field-derived LOD is valuable. Our analysis also provides evidence for additional signals common to both series, especially at a period near 120 days, which could be due to hydrological effects.
- Published
- 2008
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