Microstructure measurements and finescale parameterization assessment of turbulent mixing in the northern South China Sea
Both microscale and finescale measurements were conducted along 20°N and 21°N in the northern South China Sea (SCS) during July 2007. Spatial variability of turbulent kinetic energy (TKE) dissipation rate was examined, and two finescale parameterizations were assessed and compared. TKE dissipation rates along the 21°N section were found to be much higher than those along 20°N; in particular, remarkably high TKE dissipation rates existed near the Luzon Strait and around the Dongsha Plateau, which were likely caused by internal tides and internal solitary waves, respectively. The Gregg–Henyey scaling does not work well in the northern SCS, while the MacKinnon–Gregg scaling with a modified parameter matches the observations in both magnitude and variability. One explanation is that the large-scale/low-mode shear mainly comes from low-frequency internal waves such as internal tides, which are not described well by the Garrett–Munk spectrum.
KeywordsTKE dissipation rate Diapycnal diffusivity South China Sea Finescale parameterization
This work is jointly supported by the National Key Research and Development Program (Grant 2016YFC1401403), the Natural Science Foundation of China (Grant 41576009), the State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Science (Project LTO1601), and the Global Change and Air–Sea Interaction Project (Grants GASI-IPOVAI-01-03 and GASI-IPOVAI-01-02). We thank the US National Oceanic and Atmospheric Administration for providing the ETOPO1 data (http://www.ngdc.noaa.gov/mgg/global/global.html).
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