[A-CG38] Dynamics of Oceanic and Atmospheric Waves, Vortices, and Circulations

[ACG38-02] Energetics of the M₂ internal tides modulated by typhoons at the Luzon Strait

*Anzhou Cao^1,2, Zheng Guo³, Shuya Wang², Jinbao Song¹, Xinyu Guo² (1.Ocean College, Zhejiang University, 2.Center for Marine Environmental Studies, Ehime University, 3.Marine Science and Technology College, Zhejiang Ocean University)

Keywords:Internal tides, Typhoon Megi, Luzon Strait, Conversion, Baroclinic energy flux, Dissipation

This study investigates the influence of typhoon Megi (2010) on the energetics of the M₂ internal tides (ITs) at the Luzon Strait (LS) based on the numerical simulation. Results indicate that typhoon Megi caused intense low-frequency currents and stratification variation near the LS, which further induced significant temporal variations in the M₂ conversion, baroclinic energy fluxes and dissipation at the LS. With a condition of no background currents, typhoon Megi reduced the M₂ conversion at the LS by 4.5% and weakened the westward M₂ baroclinic energy fluxes into the South China Sea by 14.3%. Typhoon Megi did not significantly change the averaged M₂ dissipation at the LS, but it elevated the averaged local dissipation efficiency to some extent. When background currents were taken into consideration, the influence of typhoon Megi on the M₂ conversion and baroclinic energy fluxes was weakened, but the influence on the M₂ dissipation was enhanced. Moreover, idealized experiments indicate that typhoons with different tracks have different influences on the M₂ ITs. With the same typhoon characteristics (radius, maximum wind speed and translation speed), the typhoon that passes over the LS from east to west causes the largest variation in the energetics of the M₂ ITs at the LS.