Broad frequency tidal dynamics simulated by a high-resolution global ocean tide model forced by ephemerides

Abstract

Traditionally, global ocean tide models are forced by individual partial tides resulting from a decomposition of the complete lunisolar tidal potential in Fourier components. Implicitly, this approach neglects nonlinear interactions between partial tides. This can be partly compensated by a superposition of a selection of partial tides. In order to ensure the full dynamics, the Tidal Model forced by Ephemerides (TiME) incorporates the tidal potential of second degree calculated online from analytical ephemerides and utilizes the classical shallow-water equations with a horizontal resolution of 5 min globally. Interactions between partial tides generate shallow-water tides which are shown to form in extended shelf areas where they develop the highest amplitudes. However, as they propagate into the open ocean, they should be regarded as a global phenomenon. Simulations with TiME confirm that M4 is particularly pronounced in the Atlantic and suggest further areas of strong energy fluxes in the southern Pacific. MN4 is strongest in the Atlantic and MS4, 2SM2, and MK3 mainly spread out into the Indian Ocean. Copyright 2008 by the American Geophysical Union.