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Science 6 May 1994:
Vol. 264. no. 5160, pp. 830 - 832
DOI: 10.1126/science.264.5160.830
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Articles

Diurnal and Semidiurnal Variations in the Earth's Rotation Rate Induced by Oceanic Tides

R. D. Ray 1, D. J. Steinberg 2, B. F. Chao 2, and D. E. Cartwright 3

1 HSTX, NASA Goddard Space Flight Center, Code 926, Greenbelt, MD 20771, USA.
2 Geodynamics Branch, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
3 Borough House, Petersfield, Hampshire GU32 3LF, United Kingdom

Recent space-geodetic observations have revealed daily and subdaily variations in the Earth's rotation rate. Although spectral analysis suggests that the variations are primarily of tidal origin, comparisons to previous theoretical predictions based on various ocean models have been less than satisfactory. This disagreement is partly caused by deficiencies in physical modeling. Rotation predictions based on a reliable tidal-height model, with corresponding tidal currents inferred from a modified form of Laplace's momentum equations, yield predictions of tidal variations in Universal Time that agree with very long baseline interferometer observations to 2 microseconds. This agreement resolves a major discrepancy between theory and observation and establishes the dominant role of oceanic tides for inducing variation in the Earth's rotation at these frequencies.

Submitted on December 27, 1993
Accepted on March 25, 1994


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Ocean Tides for and from TOPEX/POSEIDON.
C. Le Provost, A. F. Bennett, and D. E. Cartwright (1995)
Science 267, 639-642
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