Abstract: We have rederived the periodic variations of the earth's rotation due to the tidal deformation of the earth by the sun and moon and included all terms with amplitudes ≥0.002 milliseconds (1 mm). This series applies to the mantle (plus crust) and oceans, which rotate together for characteristic tidal periods. The parameter which scales the rotational series is k/C , where k is that fraction of the Love number which causes the tidal variation in the moment of inertia of the coupled mantle and oceans while C is the dimensionless polar moment of inertia of the coupled units. If the whole earth (minus oceans) were coupled rotationally, then k = 0.30 and C = 0.33. Ocean tides increase k by 0.04. Decoupling of the fluid core from the mantle decreases k by 0.06 while C = C mantle = 0.29, since neither pressure, viscous, nor hydromagnetic coupling locks the fluid to the mantle for periods less than 5 to 25 years. From the analysis of lunar laser ranging data we find that k/C at monthly and fortnightly frequencies equals 0.99 ±0.15 and 0.99 ± 0.20 as compared with a theoretical value of 0.94 ± 0.04. In addition, we have estimated theoretically the effects of ocean tides on earth rotation, nutation and polar motion using models based on the Laplace tidal equations.
Publication Year: 1981
Publication Date: 1981-02-10
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 304
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