The nutation terms due to the variation of the dynamical ellipticity

Abstract

We present the theoretical study of the effect of zonal tides on the dynamical ellipticity of the Earth and its influence on the nutation, using the Hamiltonian theory. The numerical evaluation of the coefficients of nutation starting from the equations obtained leads to 15 new amplitudes larger than the new truncation level of the series of nutation (0.1 μas), with a relatively important contribution, larger 100 μas, to the 18.6 yr nutation. All these terms are not considered in the usual transfer function from rigid to non rigid Earth nutation.