A Simple Theory on the Dynamical Effects of a Stratified Fluid Core upon Nutational Motion of the Earth [chapter]

Tetsuo Sasao, Shuhei Okubo, Masanori Saito
1980 Nutation and the Earth's Rotation  
The theory of Molodensky (1961) on dynamical effects of a stratified fluid outer core upon nutations and diurnal Earth tides is recon structed on a new and probably much simpler ground. A theory equiva lent to Molodensky's is well represented on the basis of two linear equations for angular-momentum balance of the whole Earth and the fluid outer core, which differ from the well-known equations of Poincare (1910) only in the existence of products of inertia due to deformations of the whole Earth
more » ... of the whole Earth and fluid outer core. The products of inertia are characterized by four parameters which are easily com puted for every Earth model by the usual Earth tide equations. A reciprocity relation exists between two of the parameters. The Adams Wiliamson condition is not a necessary premise of the theory. Ampli tudes of nutations and tidal gravity factors are computed for three Earth models. A dissipative core-mantle coupling is introduced into the theory qualitatively. The resulting equations are expressed in the same form as those of Sasao, Okamoto and Sakai (1977) . Formulae for secular changes in the Earth-Moon system due to the core-mantle friction are derived as evidences of internal consistency of the theory. 165 E. P. Fedorov, M. L. Smith and P. L. Bender (eds.J, Nutation and the Earth's Rotation, 165-183.
doi:10.1007/978-94-010-9568-6_27 fatcat:dt6y27us5fgrjfd6eev2f2vanq