Nondivergent Planetary Oscillations in Midlatitude Ocean Basins with Continental Shelves

Abstract

Free oscillations in square, midlatitude basins with continental shelvesand planetary vorticity gradients are numerically computed usingthe nondivergent shallow-water equations. The topography may renda planetary mode into a family of basinwide modes, each comparableto the flat-bottom counterpart in frequency and midbasin structure.This phenomenon can be interpreted in terms of coupled planetarywave-shelf wave oscillations. The mechanism provides an alternativeto strong dissipation in explaining broadbanded planetary-wave signalssignals observed in tide guage records.