The Research Of Internal Tide And Diapycnal Turbulent Mixing In The Southern Ocean

Estimation and analysis are conducted on the observation in most regions of the ocean in the Antarctica for many years using the proper parameterization, which is chosen by comparing different parameterizations validated in past works. The observations come from the 19th, 21st, and 22nd Antarctic Research, and the experiment regions consist of ACC region, Weddell Sea, Prydz Bay and the continental shelf and slope of Maude Queen(between the Zhongshan Station and the Changcheng Station).The result derived from the model modified by Kunze (2006) compare well with the observation measured directly by TurboMAP except in the surface layer in the east of Amery ice shelf. The parameterizations validated in the deep ocean are applied to the high latitude regions successfully. The results of 2 repeat-occupation stations located in the east and west of the Amery ice shelf front show that: the semidiurnal signal dominate over the barotropic and baroclinic tide, the energy of baroclinic tide permeate downward and the mixing is typical of semidiurnal modulation.The enhanced turbulent diapycnal mixing over the broad continental shelf and slope in the Antarctica is produced by the interaction between the strong current and the rough topography. It is clear from the 3 sections of the mouth of Prydz Bay that the enhanced mixing region appears near the bottom of the continental slope, with a maximum diapycnal diffusivity of 6×10-4 m2s-1 and a maximum thickness of hundred meters. The enhanced mixing over the bottom layer of continental shelf is evident from the section between the Zhongshan and Changcheng Station. There is a divergence region with large area (particularly Antarctic Slope Front) in the whole Southern Ocean, and an enhanced mixing region with a large thickness. This conclusion can be seen from the regions along and across ACC, and the sections of Prydy Bay, especially in the Antarctic Deep Water with weak stratification. The mixing is rather intense into which plenty of Slope Water are injected, for example, the averaged diffusivity over the 4 stations in the divergence region in the east of the Weddell Sea reaches 7.42×10-4 m2s-1, and the mixing is also intense outside the Prydy Bay. It is also confirmed by the northern section of the Weddell Sea that the enhanced mixing is created by the interaction between the strong current and rough topography.