Observing the pole tide with satellite altimetry

Abstract

Almost 9 years of sea surface height observations from the TOPEX/Poseidon (T/P) satellite altimetry mission are used to observe the geocentric pole tide deformations of the sea surface. If the oceans are assumed to have an equilibrium response, then satellite altimeters effectively observe the equipotential surface that is associated with the solid Earth and ocean pole tide deformations. The long‐wavelength component of the geocentric pole tide deformations at the Chandler wobble period is observed from T/P altimetry to be consistent with the theoretical self‐consistent equilibrium response of the ocean pole tide. The geocentric pole tide explains 70% of the variance in the degree 2 order 1 spherical harmonic component of the residual sea surface heights that are observed by T/P, after removing the seasonal, inverse barometer, and lunisolar tidal effects. If the long‐wavelength component of the ocean pole tide is assumed to have an equilibrium response at the Chandler wobble period, then satellite altimetry proves to be another geodetic technique that can be used to estimate the Love number k2 at that period.