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

The 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 re-stratification by sub-mesoscale 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.