Collaborative Research: The impact of irregular small-scale topography on large-scale circulation patterns

This proposal addresses the role of rough bathymetry in generating small-scale eddies and submesoscale variability that interact with large scale currents. A combination of methods will be used in the project: analytical theories, high-resolution simulations, process-oriented models, and observations from satellite altimetry. A new multiscale closure parameterization for the HYCOM numerical model will be developed. The results will enhance understanding of fundamental physical processes controlling the interaction of oceanic flows with rough topography and improve numerical forecasts of the oceanic role in climate processes. This project addresses the need to develop explicit, accurate, and dynamically consistent parameterizations of the effects of submesoscale topography on larger scales of motion. Parameterizations of bottom roughness will be developed using an analytical method of multiscale asymptotic analysis. The methods to be used include analytical multiscale models, high-resolution simulations, implementation of the theory-based closure in HYCOM, and its validation by altimetry and roughness-resolving experiments. The numerical component includes simulations that explicitly resolve submesoscale variability of the bottom relief and their counterparts in which this variability is parameterized. The simulations range from relatively flexible process-oriented experiments to comprehensive general circulation models. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.