Numerical Simulation Of The Ocean Surface Mixed Layer Depth Influenced By The Multi-factors

The ocean surface mixed layer depth (MLD) is a very important physical parameter to describe the ocean surface mixed layer. MLD has important scientific significance and practical value for understanding of the upper ocean dynamics, thermodynamics, etc. Several major factors influencing MLD are analyzed in this paper. The definitions of the MLD are presented and a brief description of mixed layer models is given. The temporal and spatial characteristics of surface wind stress, net heat flux, evaporation, precipitation, and the difference between evaporation and precipitation (DEP) in the South China Sea (SCS) are analyzed by using monthly mean data in 2001. A foreign advanced numerical model MITgcm and a vertical mixing scheme KPP with a nonlocal boundary layer parameterization are employed. Several ideal numerical experiments are tested by modifying the existing sea surface boundary conditions. The sensitivity of the MLD simulation results influenced by surface wind stress, net heat flux and DEP is analyzed, it is shown that sea surface wind stress is the most sensitive parameters for MLD.The high resolution (1/4°×1/4°) numerical simulation in the SCS using MITgcm, grid nesting technique and several sea surface boundary conditions forced by the observational data is studied. The temporal and spatial characteristics of sea surface temperature, sea surface salinity, flow field and MLD are analyzed. The influences of the MLD by surface wind stress, net heat flux, and DEP are analyzed. Comparing the simulation result with observation data, the results suggest that MITgcm is applicable for studying MLD for SCS area.The new methods are presented to estimate the mixed-layer depth from SAR image based on the dispersion relationships obtained by using the two-layer fluid model of oceanic internal waves when the effects of Coriolis forces and steady uniform currents are considered. A internal solitary wave captured by the SAR image in the north South China Sea is analyzed by the proposed inversion methods, comparing the result with synchronized CTD data, it is shown that the models with the effect of Coriolis force and steady uniform currents are more reasonable.