摘要
基于2007年8月获得的ADCP(声学多普勒流速剖面仪)海流资料和CTD(温盐深剖面仪)水文资料,应用Gregg模型对南海中深层内波尺度的混合进行估计,同时应用Thorpe尺度对中深层存在的垂向翻转及由此引起的混合进一步分析。两种方法均显示,吕宋海峡附近上层400m的耗散率及混合率均强于18°N断面,中深层两个区域的混合率并没有显著区别。这表明吕宋海峡上层400m,可能存在更活跃的内波活动,从而产生更强的内波混合和垂向水团翻转。Gregg模型估计的耗散率和混合率量级分别为10-9W.kg-1和10-6m2.s-1。大部分CTD站位在中深层均存在垂向翻转,而且保持较高的发生率,翻转所对应的混合率并不随深度增加而减小。以上南海北部的细结构混合特征增强对南海中深层混合的认识。
Using ADCP （Acoustic Doppler Current Profiler） and CTD （Conductivity/Temperature/Depth profiler） data acquired in August 2007 and the Gregg model, the authors estimate the internal-wave-scale mixing in the intermediate and deep layers of the South China Sea. They also use the Thorpe scale to study the vertical overturns in these layers and the corresponding diapycnal diffusivity. The results by the two methods are consistent, showing that the dissipation rate and diapycnal diffusivity in the upper 400m near the Luzon Strait are larger than those at 18°N, while there is no obvious distinction in the mediate and deep layers. These results, therefore, suggest that there may be active internal waves resulting in intensive internal wave mixing and vertical overturning in the upper 400m near the Luzon Strait. The dissipation rate and diapycnal diffusivity estimated by the Gregg model are at the level of 10 9W·kg^-1 and 10^-6m^2·s^-1 , respectively. At most of the CTD stations surveyed, there always exists vertical overturning in the intermediate and deep layers and the diapycnal diffusivity estimated by the Thorpe scale does not decrease with depth. The characteristics of the fine-scale mixing reported here will facilitate the understanding of the in- termediate and deep layers of the South China Sea.
出处
《热带海洋学报》
CAS
CSCD
北大核心
2009年第3期21-28,共8页
Journal of Tropical Oceanography
基金
中国科学院知识创新工程重要方向项目(KZCX2-YW-214)
中国科学院南海海洋研究所青年人才项目(SQ200813)
中国科学院南海海洋研究所领域前沿项目(LYQY200702)
国家自然科学基金(40776008)
关键词
南海
细结构混合
耗散率
混合率
内波
South China Sea
fine-scale mixing
dissipation rate
diapycnal diffusivity
internal wave
