Coupled ocean-atmosphere interactions over oceanic boundary currents

Hyodae Seo, Woods Hole Oceanographic Institution, Physical Oceanography, Woods Hole, MA, United States
The oceanic boundary current systems are often characterized by the intense and narrow currents and the enhanced eddy activity. The SSTs and surface currents associated with the energetic oceanic mesoscale variability introduce significant spatial variations in the momentum, heat, and moisture fluxes, whose impacts extend to wind work, turbulent mixing, and Ekman pumping velocity. It is known that the two types of coupled feedback effects exist, one that arises from the mesoscale SST impacting the surface wind through modulation of atmospheric boundary layer stratification, and the other through the surface current that modulates the stress through relative wind effect. These thermal and mechanical couplings co-exist in nature but impose distinctive feedbacks on the stability and strength of the boundary currents and their extensions. Using the SCOAR (WRF-ROMS) regional coupled model simulations, this study aims to separate and diagnose these two feedback effects and explore their spatial scale dependence of the coupling. The study mainly focuses on the Eastern India Coastal Current and the accompanied eddy fields in the summertime Bay of Bengal, but the result will also be compared with the prior studies for the other summertime boundary currents systems including the California Current and the Somali Current.