Issue |
A&A
Volume 438, Number 3, August II 2005
|
|
---|---|---|
Page(s) | 1149 - 1161 | |
Section | Celestial mechanics and astrometry | |
DOI | https://doi.org/10.1051/0004-6361:20042210 | |
Published online | 18 July 2005 |
Atmospheric and oceanic excitation of the rotation of a three-layer Earth
1
Royal Observatory of Belgium, Avenue Circulaire 3, 1180 Brussels, Belgium e-mail: v.dehant@oma.be
2
Institut de Physique du Globe, Paris, France
Received:
19
October
2004
Accepted:
24
February
2005
In this paper, we evaluate the nutational Earth response to the excitation exerted by a surface fluid (atmosphere, ocean, and hydrology) for a simple Earth model, constituted of three homogeneous layers: a solid deformable inner-core, a liquid outer core, and an elastic mantle. Our formula, valid in the quasi-diurnal frequency band, includes two resonances, at the Free Core Nutation (FCN) and the Free Inner-Core Nutation (FICN). Additionally, we have evaluated the amplitudes of those wobbles in response to a random noise excitation. We show that, compared with the FCN signal, the resonance at the FICN frequency induced by a surface fluid layer only induces a very small signal in the Earth rotation, and that, with an excitation comparable to the one available at the FCN, the FICN would generate a signal at the Earth surface at the sub-micrometer level.
Key words: Earth / reference systems
© ESO, 2005
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