A CASE STUDY OF COLD EDDY ENHANCED MIXING IN THE NORTHERN SOUTH CHINA SEA
Mesoscale energy can be dissipated in a nonlinear system of the ocean by small-scale turbulent mixing.Clarifying the effect of mesoscale eddies on turbulent mixing is important to improve the understanding of cross-scale energy transfer and developing climate model simulations.Based on the Thorpe-scale and fine-scale parameterization methods,the spatial structure of turbulent mixing was estimated using underwater glider data in the South China Sea.Results show that the mixing was enhanced at the edges of cold eddy,the intersection of cold and warm eddies,and the region of warm eddy;and the diffusivity of cold eddy(warm eddy)can reach up to O(10-3m2/s)[O(10-4 m2/s)],with an average diffusivity of about 9.0×10-5 m2/s(6.2× 10-5 m2/s),which is 4(2.8)times higher than that of the eddy-free condition.Seawater masses with Richardson number less than 0.25 appear at the edge of the cold eddy,cold-warm eddy convergence,and the warm eddy,indicating that the shear instability is conducive to the enhancement of local turbulent mixing.
cold eddyturbulent mixingdiffusivitySouth China Sea
万方数据
维普
