Rotationally acceptable ocean tide models for determining the response of the oceans to atmospheric pressure fluctuations

Abstract

Suitably generalized, ocean tide models can be used to determine the oceans' response to atmospheric pressure forcing; but the huge range of spatial and temporal scales of that forcing limits the relevance of state-of-the-art tide modeling techniques, like data assimilation, for such determinations. With an interest in its effects on Earth's rotation, in 1998 I employed a generalized but non-assimilating spherical harmonic tide model to determine the oceanic response to pressure forcing, however restricting its application to time scales exceeding a few days. This article revisits that spherical harmonic model in an attempt to improve its rotational predictions of short-period tides. We find that increasing the resolution of the model ocean does not by itself affect the tidal solution much, but varying the model's frictional parameters can produce diurnal tides whose effects on Earth's polar motion are similar to those of a variety of other ocean tide models. Such an improved model will allow our calculations of the oceans' dynamic response to pressure forcing, and the effects of that response on Earth's rotation, to be extended down to diurnal time scales. Copyright 2010 by the American Geophysical Union.