Right‐side cooling and phytoplankton bloom in the wake of a tropical cyclone

Abstract

AbstractThe rightward tendency (in northern hemisphere) of enhanced phytoplankton bloom often observed in the wake of a tropical cyclone has commonly been attributed to the rightward bias of mixing due to stronger wind and wind‐current resonance. We demonstrated using a high‐resolution biophysical model that vertical mixing alone resulted only in weak asymmetry after the passage of the storm. The enhanced bloom was caused instead by decreased turbulence due to restratification by submesoscale recirculation cells preferentially produced on the right side, rightward shift of cool isotherms, and spin‐up of a subsurface jet. We showed using a two‐time scale asymptotic expansion that these slower‐evolving features were forced by resonance Reynolds stresses of the energetic and rapidly oscillating near‐inertial internal waves.