Investigation Of Upper Ocean Response To Typhoon Using Multiple Satellites Observation And Numerical Simulation

The mechanisms of oceanic response and feedback to tropical cyclones(TCs)are hot topics on oceanic and atmospheric research,and hold a key for skillful forecasts of tropical cyclone intensity and associated marine environmental variations.Knowledge of oceanic responses to TCs is helpful to understand the environment of the ocean,improve the forecast of TCs and prevent as well as reduce natural disasters.With a combination of multiple-satellite observations,in situ observations and numerical simulations,this paper focuses on the characteristics and mechanisms of upper ocean surface and subsurface(temperature,salinity,current,and ocean heat content)response to TCs.We investigated ocean surface and subsurface physical responses to the typhoon case(Typhoons Kalmaegi(2014)and Sarika(2016)),utilizing synergistic multiple-satellite observations,in situ measurements,and numerical simulations.We found significant typhoon-induced sea surface cooling using satellite sea surface temperature(SST)observations and numerical model simulations,and the maximum amplitudes were 6 ? and 4.2 ? for Typhoons Kalmaegi and Sarika,respectively.Satellite salinity observations showed that the maximum increase of sea surface salinity(SSS)was 2.2 psu on the right side of Typhoon Sarika's track,and the maximum decrease of SSS was 1.4 psu on the left.This SSS seesaw response phenomenon is related to the asymmetrical rainfall on both sides of the typhoon track.Acoustic Doppler Current Profilers measurements and numerical simulations both showed that subsurface current velocities rapidly increased as the typhoon passed,with peak increases of up to 1.19 m/s and 1.49 m/s.Typhoon-generated SST cooling and current velocity increases both exhibited a rightward bias associated with a coupling between typhoon wind-stress and mixed layer velocity.This work systematically studies the sea surface temperature and salinity induced by typhoons in the Western North Pacific subtropical ocean and South China Sean using multiple satellite observations.All twelve typhoon cases passing the study domain in 2016 were examined in detail.We confirmed that the strong and the slow moving typhoons induced sea surface temperature cooling,and the weak response typhoons and faster moving typhoons caused the temperature responses relatively weak.For salinity response,we found the strong and slow moving typhoons induce sea surface salinity increased,while the weak andfaster-moving typhoons casued sea surface decreased.