Reconstructing the upper ocean thermal profiles using one-dimensional numerical model

The observation data for 5 d at a station in the South China Sea is presented. After brief analysis of the wind speed, air temperature from the ship-borne meteorological instruments and temperature and salinity profiles from the CTD (conductivity, temperature, depth recorder) data, the authors find that the CTD casts are too sparse for us to understand the diurnal evolution of the thermal structure in the upper ocean. A one-dimensional (1D) numerical code based on Mellor-Yamada turbulence closure model is used to reconstruct the upper ocean thermal structure, utilizing the atmospheric forcing data from ship-borne weather station. The simulation results show good agree- ment with the observational data; the significance of breaking waves is also briefly discussed. The evolution of turbulence kinetic energy (TKE) and the contribution from shear production and buoy- ancy production are discussed respectively. Finally, several possible factors which might influence the numerical results are briefly analyzed.