热带海洋学报 ›› 2009, Vol. 28 ›› Issue (3): 21-28.doi: 10.11978/j.issn.1009-5470.2009.03.021

• 海洋物理学 • 上一篇    下一篇

南海北部中深层细结构混合研究

卢著敏1,陈桂英2,尚晓东2   

  1. 1. 中国科学院南海海洋研究所热带海洋环境动力学重点实验室
  • 收稿日期:2008-10-30 修回日期:2009-03-23 出版日期:2009-05-31 发布日期:2010-02-05
  • 通讯作者: 尚晓东

Study of fine-scale mixing in intermediate and deep layers of the South China Sea

Zhumin Lu1, CHEN Gui-Yang2,SHANG Xiao-Dong2   

  • Received:2008-10-30 Revised:2009-03-23 Online:2009-05-31 Published:2010-02-05

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10–6 m2?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。

Abstract: 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 10–9 W?kg–1 and 10–6 m2?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 intermediate and deep layers of the South China Sea.

Key words: South China Sea, fine-scale mixing,dissipation,diapycnal diffusivity

中图分类号: 

  • P733