南海北部冷涡增强混合的个例研究  

A CASE STUDY OF COLD EDDY ENHANCED MIXING IN THE NORTHERN SOUTH CHINA SEA

作　　者：韩丽丽 司宗尚 庞重光[2,3] 闫晓梅 陈明[1] 俞建成 HAN Li-Li;SI Zong-Shang;PANG Chong-Guang;YAN Xiao-Mei;CHEN Ming;YU Jian-Cheng(College of Mathematics and System Science,Shandong University of Science and Technology,Qingdao 266590,China;Key Laboratory of Ocean Circulation and Waves,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;Laboratory for Ocean and Climate Dynamics,Laoshan Laboratory,Qingdao 266237,China;Shenyang Institute of Automation,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]山东科技大学数学与系统科学学院,山东青岛266590 [2]中国科学院海洋研究所海洋环流与波动重点实验室,山东青岛266071 [3]崂山实验室海洋动力过程与气候功能实验室,山东青岛266237 [4]中国科学院沈阳自动化研究所,辽宁沈阳110016

出　　处：《海洋与湖沼》2024年第3期627-637,共11页Oceanologia Et Limnologia Sinica

基　　金：国家重点研发计划项目,2021YFC2803104号;崂山实验室科技创新项目,LSKJ202201502号。

摘　　要：海洋作为一个多尺度非线性系统,中尺度能量可以通过小尺度的湍流混合耗散,明晰中尺度涡对湍流混合的影响对于提高对跨尺度能量传递的认识和改进气候模式模拟具有重要作用。基于Thorpe-scale和细尺度参数化方法,利用2015年水下滑翔机在南海观测的水文数据对湍流混合空间结构进行重建与分析。结果表明,在冷涡边缘、冷暖涡交汇和暖涡区域出现混合增强现象,冷涡(暖涡)的扩散系数最高可达O(10^(-3) m^(2)/s)[O(10-4 m^(2)/s)],平均扩散系数约为9.0×10^(-5) m^(2)/s(6.2×10^(-5) m^(2)/s),是无涡状态下的4(2.8)倍。冷涡边缘、冷暖涡交汇处和暖涡区域出现理查森数小于0.25的海水水团,表明该处发生剪切不稳定有利于增强湍流混合。并且较小的理查森数大量出现在冷涡及冷暖涡交汇处,这也是冷涡处的扩散系数比暖涡处大的原因。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(10-3 m^(2)/s)[O(10^(-4) m^(2)/s)],with an average diffusivity of about 9.0×10^(-5) m^(2)/s(6.2×10^(-5) m^(2)/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.

关 键 词：冷涡 湍流混合 扩散系数 南海 

分 类 号：P731[天文地球—海洋科学]