Journal of Tropical Oceanography ›› 2017, Vol. 36 ›› Issue (4): 67-76.doi: 10.11978/2016106CSTR: 32234.14.2016106

• Orginal Article • Previous Articles     Next Articles

The seasonal and sporadic variation of the spreading of a small tropical river plume and its associated dynamics

Junpeng ZHAO1(), Yihan LI2, Wenping GONG1()   

  1. 1. School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China
    2. Zhongdianke Marine Information Technology Research Inc., Beijing 100043, China
  • Received:2016-10-24 Revised:2017-02-10 Online:2017-07-20 Published:2017-07-26
  • Supported by:
    National Natural Science Foundation of China (40976052, 41576089)

Abstract:

A small river plume is distinctly different from a large river plume, more controlled by the variation of river discharge and wind. Taking the Wanquan River plume in Hainan as an example, we focus on the seasonal variation of a small river plume and its response to a river flood event in this study. The dynamics of the plume is investigated through momentum balance analysis. The results indicate that the spreading of the Wanquan River plume features a conspicuously seasonal variability, with the spreading direction being mostly downstream during winter, and being offshore or upstream during summer. The spreading extent is the largest in August and the smallest in December and January. A two-day flood event can greatly increase the plume extent; however, the effect of this river flood quickly disappears, with a recovery time in the order of 3 days. The momentum balance shows the balance in the far-field region is mostly a geostrophic one in the normal direction, while it is dominated by pressure gradient and friction in the stream-wise direction. In the near-field region, the Coriolis force is negligible in the normal direction, which is greatly different from that in the mid-latitude river plume.

Key words: small river plume, seasonal variation, flood event, momentum balance, Hainan

CLC Number: 

  • P731