热带海洋学报 ›› 2016, Vol. 35 ›› Issue (6): 1-9.doi: 10.11978/2016009CSTR: 32234.14.2016009

• 海洋水文学 •    下一篇

南海东沙海区冬季跨陆坡运动的动力诊断分析

黄孝荣1, 2, 王强1, 周伟东1, 周生启1   

  1. 1. 中国科学院南海海洋研究所, 热带海洋环境国家重点实验室, 广东 广州 510301;
    2. 中国科学院大学, 北京 100049
  • 收稿日期:2016-01-18 修回日期:2016-05-18 出版日期:2016-11-30 发布日期:2016-12-15
  • 通讯作者: 周生启。E-mail: sqzhou@scsio.ac.cn
  • 作者简介:作者简介:黄孝荣(1990-), 男, 福建省福州市人, 硕士研究生, 主要从事海洋数值模拟研究。E-mail: xrhuang@scsio.ac.cn
  • 基金资助:
    国家自然科学基金项目(41349907、41376026、41406038、41430968); 中国科学院战略性先导科技专项项目(A类) (XDA11030302)

A study of the cross-shelf flow around Dongsha Island in the South China Sea in winter using a diagnostic model

HUANG Xiaorong1, 2, WANG Qiang1, ZHOU Weidong1, ZHOU Shengqi1   

  1. 1. State Key Laboratory of Tropical Oceanography (South China Sea Institute of Oceanology, Chinese Academy of Sciences), Guangzhou 510301, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China;
  • Received:2016-01-18 Revised:2016-05-18 Online:2016-11-30 Published:2016-12-15
  • Contact: ZHOU Shengqi. E-mail: sqzhou@scsio.ac.cn
  • Supported by:
    National Natural Science Foundation of China (41349907、41376026、41406038、41430968); The Strategic Priority Research Program of the Chinese Academy of Sciences (XDA11030302)

摘要: 基于普林斯顿海洋模式(POM), 利用全球海洋温盐集(WOA13)气候态温盐数据对南海环流进行诊断计算, 分析东沙海区冬季气候态跨陆坡运动特征。诊断结果表明: 跨陆坡运动的水平和垂向断面分布, 反映出该海区跨陆坡运动存在反对称结构, 即东沙岛以东向陆架方向运动、以西向外洋方向运动。根据正压涡度平衡方程逐项分析, 探讨了东沙海区跨陆坡运动的动力机制, 研究表明: 地形与斜压联合效应项(joint effect of baroclinicity and bottom relief, JEBAR)和地转位势涡度平流项(advection of the geostrophic potential vorticity, APV)主导了涡度平衡, 平流项和扩散项作用次之, 且JEBAR、APV及平流扩散各项在东沙岛东西两侧均表现为正负号相反分布; 相比而言, 海表风应力项和海底摩擦力项的影响为小量。东沙海区密度场相对于地形的不均匀分布, 使得东沙以东JEBAR分布为正、以西JEBAR分布为负, 这种分布是导致反对称的跨陆坡运动发生的主要内在机制, 且东沙岛地形和不均匀密度场分布是这种动力机制得以维持的主要原因。

关键词: 诊断模型, 跨陆坡运动, 涡度平衡, 南海

Abstract: This paper focuses on the cross-shelf flow around Dongsha Island in the South China Sea. Based on the diagnostic model of Princeton Ocean Model (POM) we analyzed the climatologic character of the ocean circulation around Dongsha Island using World Ocean Atlas 2013 (WOA13) climatological temperature and salinity data in winter. We found that an antisymmetric structure exists in the cross-shelf flow around Dongsha Island by examining the horizontal and vertical velocity distributions of cross-shelf flow. In addition, analyses of the barotropic vorticity balance showed that there are five terms related to the cross-shelf flow. The joint effect of baroclinicity and bottom relief (JEBAR) term and the advection of geostrophic potential vorticity (APV) term play dominated roles in the vorticity balance, and the advection and diffusion terms are secondary. The influences of sea surface wind stress and sea floor friction terms are minor. Moreover, the JEBAR, APV, advection, and diffusion terms indicate similar antisymmetric distributions around Dongsha Island. The uneven distribution of sea water density relative to the local topography causes the density gradient along isobaths. Therefore, the JEBAR term shows positive and negative at the east and west of Dongsha Island, respectively, which might be responsible for the generation of the cross-shelf flow. Topography of Dongsha Island and uneven distribution of sea water density are the primary causes that maintain these dynamic processes.

Key words: diagnostic model, cross-shelf flow, vorticity balance, South China Sea