Modulating effect of the divergent and rotational wind induced by mesoscale sea surface temperature perturbations in the Kuroshio Extension

Abstract

Mesoscale wind stress perturbations induced by sea surface temperature (SST) perturbations have a feedback effect on the ocean by influencing air–sea heat and momentum fluxes. Unlike the thermal feedback mechanism, which is well understood, the momentum feedback still needs to be studied, especially the respective roles of divergent and rotational wind components. In this study, momentum feedback was examined using an ocean model and an empirical equation, which solved wind stress field perturbations from their divergence and curl estimated from time‐evolving downwind and crosswind SST gradients. Through several numerical experiments, it was found that both the divergent and rotational wind can induce positive and negative temperature changes at varying regions and depths. This modulating effect is weak, with a maximum SST change of about 0.4°C on average, but it can reach the deep ocean beyond 1000 m.