Open AccessDynamic Ocean‐Tide Effects On Earth's Rotation
Author(s) -
Dickman S. R.
Publication year - 1993
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1993.tb01180.x
Subject(s) - earth's rotation , nutation , polar motion , rotation (mathematics) , geodesy , geophysics , geology , tidal waves , moment of inertia , atmospheric tide , physics , mechanics , inertia , angular momentum , harmonic , classical mechanics , geometry , ionosphere , mathematics , thermosphere , quantum mechanics , astronomy
Summary This 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.