Yang Qingxuan, Nikurashin Maxim, Sasaki Hideharu, Sun Hui, Tian Jiwei
Physical Oceanography Laboratory/CIMST, Ocean University of China, and Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
ARC Centre of Excellence for Climate Extremes, Sydney, Australia; University of Tasmania, Hobart, Australia.
Sci Rep. 2019 Jan 24;9(1):556. doi: 10.1038/s41598-018-36610-x.
It is reported that turbulent mixing is enhanced in the South China Sea (SCS), and it is highly variable in both space and time. Generation and breaking of internal tides has been identified as the main process to drive turbulent mixing in the SCS, while the contributions from other processes are not clear enough. Here we investigate the potential contribution from mesoscale eddies to turbulent mixing in the SCS using a high resolution numerical simulation. Our results show that mesoscale eddies in the SCS effectively dissipate over complex rough topography and indicate that the generation of submesoscale motions and lee waves are two pathways for the transfer of mesoscale eddy energy down to small dissipation scales. The energy loss from mesoscale eddies near the Xisha Islands is estimated to be sufficient to sustain turbulent kinetic energy dissipation rate of O (10) W/kg. This study suggests an alternative and potentially efficient mechanism to internal tides for the local maintenance of turbulent mixing in the SCS.
据报道，南海的湍流混合增强，且在空间和时间上具有高度变异性。内潮的产生和破碎已被确定为驱动南海湍流混合的主要过程，而其他过程的贡献尚不够明确。在此，我们使用高分辨率数值模拟研究中尺度涡旋对南海湍流混合的潜在贡献。我们的结果表明，南海的中尺度涡旋在复杂粗糙地形上有效耗散，并表明亚中尺度运动和背风波的产生是中尺度涡旋能量向下传递到小耗散尺度的两条途径。据估计，西沙群岛附近中尺度涡旋的能量损失足以维持O(10)W/kg的湍动能耗散率。这项研究提出了一种替代内潮的、可能有效的机制，用于维持南海局部的湍流混合。
