Tidal studies from the perturbations in satellite orbits

Abstract
Tidal perturbations in the orbits of close Earth satellites permit the Love number K 2 and the phase lag ε 2 of the tidal effective Earth to be estimated. These parameters differ significantly from the nominal values of K 2 = 0.30 and ε 2 < 0.5° that would be expected if only the solid tide was important. This difference is due to the contribution of the oceans to the total tidal potential. This contribution is less well known than the solid tide potential and the study of the orbital perturbations permits an estimation of some of the long wavelength variations in the ocean tide. In this paper we discuss the method and the results obtained from two satellites for the S 2 and M 2 ocean tide. These tidal parameters are compared with and combined with numerical models of these tides to give improved parameters to be used in any orbital theory.