Worldwide Synthetic Gravity Tide Parameters

Abstract

Synthetic gravity tide parameters (amplitude factors and phase leads) have been computed for the waves MF, Q1, O1, P1, K1, N2, M2, S2 and K2 in a worldwide 1° x 1° grid at 26995 grid points located mainly on land. The gravity tide parameters have been derived from gravity tide amplitudes of the Tamura (1987) tidal potential referring to a rigid Earth model, body tide amplitude factors using a model of an ocean-free, elastic, rotating, isotropic and ellipsoidal Earth with liquid outer core (Wahr 1981, Dehant 1987), and from ocean tide gravitation and load using a 1° x 1° ocean tide model (Schwiderski 1980). The synthetic gravity tide parameters have been compared at 31 European gravity tide stations selected from the data base DB92 of the International Center for Earth Tides (Melchior 1994) and show rms differences of 0.79% and 0.87% for the amplitude factors and 0.24° and 0.48° for the phase leads of the main waves 01 and M2 resp.

The synthetic gravity tide parameters have successfully been used to compute gravity tide corrections for the adjustment of the Unified European Gravity Network 1994 (Boedecker et al. 1994) and may be usefull for other gravity surveys in the future. They are made available to public domain together with a program to compute gravity tides using the tidal potential developments of Cartwright-Tayler-Edden (1973), Büllesfeld (1985) or Tamura (1987) by INTERNET electronic network:

Table 1

The files wload.dat and wparm.dat have been compressed under UNIX operation system (wload.dat.Z 1681.930 kB and wparm.dat.Z 1397.799 kB) in order to speed up the file transfer. They have to be uncompressed after transfer to your computer (“uncompress wload.dat” and “uncompress wparm.dat”).