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Dynamic ocean-tide effects on Earth's rotationThis article develops 'broad-band' Liouville equations which are capable of determining the effects on the rotation of the Earth of a periodic excitation even at frequencies as high as semi-diurnal; these equations are then used to predict the rotational effects of altimetric, numerical and 32-constituent spherical harmonic ocean-tide models. The rotational model includes a frequency-dependent decoupled core, the effects of which are especially marked near retrograde diurnal frequencies; and a fully dynamic oceanic response, whose effects appear to be minor despite significant frequency dependence. The model also includes solid-earth effects which are frequency dependent as the result of both anelasticity at long periods and the fluid-core resonance at nearly diurnal periods. The effects of both tidal inertia and relative angular momentum on Earth rotation (polar motion, length of day, 'nutation' and Universal Time) are presented for 32 long- and short-period ocean tides determined as solutions to the author's spherical harmonic tide theory. The lengthening of the Chandler wobble period by the pole tide is also re-computed using the author's full theory. Additionally, using the spherical harmonic theory, tidal currents and their effects on rotation are determined for available numerical and altimetric tide height models. For all models, we find that the effects of tidal currents are at least as important as those of tide height for diurnal and semi-diurnal constituents.
Document ID
19930045453
Document Type
Reprint (Version printed in journal)
Authors
Dickman, S. R.
(New York State Univ. Binghamton, United States)
Date Acquired
August 16, 2013
Publication Date
March 1, 1993
Publication Information
Publication: Geophysical Journal International
Volume: 112
Issue: 3
ISSN: 0956-540X
Subject Category
Geophysics
Funding Number(s)
CONTRACT_GRANT: NAG5-145
Distribution Limits
Public
Copyright
Other
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