Tidal Spherical Harmonics Tables

Spherical harmonic decompositions of the tides play an important role in many aspects of geodesy. This is especially so for the degree-1 and degree-2 components. The degree-1 components are directly proportional to the tidal displacements of the geocenter. The degree-2 components are related to the inertia-tensor contributions to polar motion and Universal Time, and certain of them are directly proportional to the rate of working of gravitational tidal forces. Because of the importance of these low-degree terms, the IERS Special Bureau for Tides is tabulating a large number of estimates of them from various models. The more reliable ocean models are based on Topex/Poseidon altimeter measurements, supplemented as necessary by hydrodynamic models in polar seas.

The spherical harmonic coefficients tabulated on these pages follow a consistent convention. In general, only a few of the lower degree and order coefficients are given, with some selected higher degree coefficients added because of their importance to satellite geodesy.


Ocean Tides
Topex/Poseidon Model GOT99.2 (R Ray, 1999).
Topex/Poseidon Model TPXO.4a (G Egbert, 1999).
Topex/Poseidon Model TPXO.6.2 (G Egbert, 2002).
Topex/Poseidon-Hydrodynamic Model FES2004 (F Lyard et al., 2006).

Atmospheric Tides
Model from barometric station data (R Ray, JASTP, 2001).

Return to IERS Special Bureau for Tides home page.

Still under construction.

Last Updated: June 4, 2007
Web Curator: Richard Ray