Theoretical considerations concerning polar motion

The polar motion of the earth is analyzed in terms of the Sasao et al. (1980) theory. The formulas of Sasao et al., and the variational principle of Poincare, upon which the Sasao et al. theory is based, are discussed. The derivation of the potential energy of elastic deformation, and the lunisolar diurnal polar motion are examined. Examples in which the Sasao et al. theory is applied to the study of polar motion for a liquid core model and free polar motion are presented. It is noted that the Sasao et al. theory is useful for examining polar motion.