Marine Hydrography

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

  • HUANG Xiaorong ,
  • WANG Qiang ,
  • ZHOU Weidong ,
  • ZHOU Shengqi
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  • 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 date: 2016-01-18

  Revised date: 2016-05-18

  Online published: 2016-12-15

Supported by

National Natural Science Foundation of China (41349907、41376026、41406038、41430968); The Strategic Priority Research Program of the Chinese Academy of Sciences (XDA11030302)

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.

Cite this article

HUANG Xiaorong , WANG Qiang , ZHOU Weidong , ZHOU Shengqi . A study of the cross-shelf flow around Dongsha Island in the South China Sea in winter using a diagnostic model[J]. Journal of Tropical Oceanography, 2016 , 35(6) : 1 -9 . DOI: 10.11978/2016009

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