3D modeling of mixed-layer deepening caused by typhoon in the South China Sea

Principal Investigator: Prof. Pan Jiayi

Start Date: 2013/01/01
End Date: 2014/05/30
Type of Grant: Direct Grant

The South China Sea is a typical monsoon climate region. Every year there are more than ten typhoons or tropical storms affecting the South China Sea including Hong Kong area. Typhoons inject substantial momentum into the upper ocean mixed-layer for a short duration along their passages. Strong typhoon winds generate turbulent entrainment and upwelling that cause subsurface cold water to entrain and uplift into surface layer, resulting in cooling of surface water and deepening of upper mixed-layer. In this study, we propose to use a three-dimensional numerical ocean model, namely Region Ocean Modeling System (ROMS) coupled with an atmospheric model, Weather Research and Forecasting (WRF) to simulate the mixed-layer deepening process caused by typhoon in the South China Sea. The objectives of the study are to: 1) investigate the dynamic mechanism of the mixed-layer deepening induced by typhoon through different model schemes, 2) explore the correlation of the mixed-layer deepening with seasonal thermocline depth, and 3) analyze the energy conversion after typhoon passage and the generation mechanism of near-inertial baroclinic waves in the mixed-layer. The results of the proposed study will improve the understanding of the ocean upper layer dynamics under extreme wind condition. This project will be an initiative of a major project for investigating typhoon process.