| 摘要: |
| 基于2012年8月12日至9月5日中国南海海洋湍流微结构剖面仪(TurboMap)观测资料和温盐深剖面仪(CTD)资料, 对南海中南部海域上层500m以浅的混合过程进行了分析。南海次表层高温高盐的水团和中层低温低盐的水团构成的垂向温盐环境, 利于在该深度范围内盐指的发育。通过盐指与湍流相关参数的计算, 评估了盐指在南海上层跨越等密面混合的作用。结果表明南海中部(18°N)相对于南海南部呈现高的温度耗散率(χ)、高的混合效率(Γ)、低湍动能耗散率(ε)及低浮性雷诺数(Rε)等特征, 即中部盐指信号明显强于南部。但整体海域仍然呈现出“低Γ; 高Rε”的湍流特征, 表明盐指对混合的贡献较小, 南海中南部的上层混合还是以湍流混合为主导。另外, 南海南部的混合强于中部, 且呈现出整体水柱均具有较强混合的特征, 其原因可能和内潮与南部相对较浅而复杂的地形相互作用有关。 |
| 关键词: 南海 盐指 混合 耗散率 |
| DOI：10.11693/hyhz20140300083 |
| 分类号: |
| 基金项目:中国科学院战略性先导科技专项项目(A 类), XDA11030302 号; 国家自然科学基金项目41176027 号, 41476167 号; 科技基础性工作专项项目, 2008FY110100 号; 热带海洋环境国家重点实验室自主研究项目, LTOZZ1304 号 |
相关附件： tiff格式插图 |
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| SALT FINGER AND TURBULENT MIXING IN THE UPPER LAYER OF THE CENTRAL SOUTHERN SOUTH CHINA SEA |
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Lu Yuanzheng,Zhou Shengqi,Cen Xianrong,Guo Shuangxi and Shang Xiaodong
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South China Sea Institute of Oceanology, Chinese Academy of Sciences,State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences,State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences,State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences,State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences
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| Abstract: |
| Profiles of a free-falling microstructure instrument (TurboMap) and conductivity-temperature-depth (CTD) were obtained in the central-southern South China Sea during Aug. 12—Sep. 5 in 2012. The characteristics of diapycnal mixing above 500m were analyzed. We found that the subsurface water is warm and salty and the intermediate water is relatively cold and fresh, which favors the formation of salt fingers. Compared to the diapycnal mixing in the southern region, temperature dissipation rate (χ) and mixing efficiency (Γ) are high but turbulent kinetic energy dissipation (ε) and the Reynolds number (Rε) of buoyancy are low in the central region, indicating a stronger salt finger in the central region. However, the contribution of salt fingers to the diapycnal mixing is very weak as Γ is low and Rε is high, which means that the turbulent mixing is stronger in the southern than in the central regions. In addition, the diapycnal mixing in the southern South China Sea is stronger than that in the central region. The strong mixing occurs throughout the whole water column in the southern South China Sea, which may be ascribed to the interaction between the internal waves and the topography. |
| Key words: South China Sea salt finger diapycnal mixing dissipation rate |
