IMPACTS OF WAVE-INDUCED TURBULENT MIXING ON TYPHOON CHARACTERISTICS

Abstract

 Turbulent mixing in ocean upper layer induces cooling of sea surface temperature (SST) and reductions of heat flux from ocean to typhoon. Sea surface turbulent kinetic energy (TKE) induced by wave dissipation is one of the main source of upper layer turbulence. In this study, two kinds of numerical experiments targeting typhoon Neoguri (2014) have been conducted, hindcast and idealized experiment under fixed atmospheric condition. The results of these experiments show that larger surface TKE flux results in great viscosity in upper layer, which reduces surface current velocity. Surface TKE also accelerates “weak mixing” inside of mixing layer, and then enhances the SST cooling. In addition of the impacts in mixing layer, surface TKE flux stimulates “strong mixing” and wind-induced internal wave which is excited beneath mixing layer. Because of the shallow mixed layer, the strong mixing gives feedback to surface current and SST. These differences due to surface TKE flux also impact on atmospheric condition of typhoon such as sea level pressure through sea surface heat flux. This implies the importance of wavedependent surface TKE for typhoon simulation.