The Impact of Small-Scale Topography on Large-Scale Ocean Dynamics

Abstract

Bottom topography influences the oceanic dynamics in a variety of ways, depending on its height, spatial scale, and on the flow regime. A physically relevant situation, which can be partly investi gated analytically, is that of a topography whose scale is much smaller th an th e typi cal scale of th e moti on. Assuming periodic or random topography and small-amplitude flow, th e standard technique of homogenizat ion can be appli ed to derive averaged, or homogenized, evolution equations for the large-scale flow. In such equations, th e usual (small-scale) topographic ter ms are replaced by non-tr ivial averaged terms which account for the large-scale effect of topography. The homogenization approach can thus be interpreted as providing an asymptotically consistent parameterization of topography in large-scale models.