Microstructure observations in the upper layer of the South China Sea

A general pattern for turbulent mixing in the upper layer of the South China Sea (SCS) is presented based on TurboMAP measurements in April and May 2010. The turbulence level decreased significantly overall from north to south, and weakened from east to west in the northern SCS. The average dissipation rate north of 18°N reaches 1.69 × 10^?8 W/kg, approximately six times larger than that south of 18°N. The mean mixing efficiency in the SCS is 0.2, with a maximum of 0.31 near the Luzon Strait. At one repeatedly occupied station located in the central deep basin, the dissipation rate varies diurnally in the mixed layer and pycnocline due to diurnal heating and cooling by solar radiation and local barotropic tide, respectively.