Disentangling wavy and vortical motions in concurrent snapshots of the sea surface height and velocity

Abstract

Wide-swath satellite missions, such as Surface Water and Ocean Topography (SWOT) and Ocean Dynamics and Sea Exchanges with the Atmosphere (ODYSEA), will provide quasi-concurrent observations of the two-dimensional sea surface height and velocity. Thanks to their high spatial resolution, the spatial features of both vortical and wavy oceanic motions are expected to be captured by these observations. A natural question is whether one can disentangle vortical and wavy motions in these snapshot observations. This issue has attracted some efforts, but crucial progress remains to be made. Here, assuming that only a single concurrent snapshot of the sea surface height and velocity is available, we pursue a dynamical approach for disentangling vortical and wavy motions. This is realized by noting that wavy motions do not induce potential vorticity anomalies. A proof-of-concept application using an output of a realistic high-resolution numerical simulation suggests that the proposed approach is simple and efficient, and is particularly useful for separating wavy and vortical motions in observations by wide-swath satellite missions.