A Coupled Discrete Wave Model MRI-II

Abstract

An ocean wind-wave prediction model MRI-II is developed on the basis of the energy balance equation which contains five energy transfer processes, namely, the input by the wind, the non-linear transfer among the components of windsea by resonant wave-wave interactions, wave breaking, frictional dissipation and the effect of opposing winds. The non-linear energy transfer is expressed implicitly together with the wind effect by Toba’s one-parameter representation of windsea, but neither swell-swell nor swell-windsea resonant interactions are considered. Hypothetical assumptions are introduced to describe wave breaking effects. The numerical constant required in the assumptions of wave breaking is determined through trial test runs for a hindcast performed on the Northwestern Pacific Ocean. The results of the hindcast and numerical experiments of the SWAMP test cases show that MRI-II outforms our old model MRI both in describing growth stages of windsea and in application to actual wind fields.