Global distribution of the decay timescale of mixed layer inertial motions observed by satellite-tracked drifters

Abstract

The decay timescale of mixed layer inertial amplitudes has been estimated from satellite tracked drifter trajectories from 1990 to 2004 as the e-folding timescale of the temporal correlation functions. The decay timescales increase with latitude in all basins except the North Atlantic. A beta dispersion model shows that dephasing leads to meridional variations of the decay timescale in the North Pacific and the Southern Ocean, but meridional variations of the buoyancy structure in the North Atlantic act to compensate the beta effect, leading to a lack of meridional variation of the decay timescale in that ocean.