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Summertime Changjiang River plume variation during 1998–2010
Author(s) -
Bai Yan,
He Xianqiang,
Pan Delu,
Chen ChenTung Arthur,
Kang Yan,
Chen Xiaoyan,
Cai WeiJun
Publication year - 2014
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2014jc009866
Subject(s) - plume , environmental science , discharge , oceanography , monsoon , climatology , spatial variability , atmospheric sciences , geology , meteorology , drainage basin , geography , cartography , statistics , mathematics
Using an improved satellite‐derived salinity algorithm in the East China Sea (ECS), we presented and examined a general view on summertime Changjiang River plume variation during 1998–2010. Three types of plume shapes were identified: (1) the commonly known northeastward transportation, (2) a case in which most of the plume water crossed the Cheju Strait into the Tsushima‐Korea Straits with only a small fraction staying on the shelf of the ECS, and (3) a rare case in which the plume front moved southeastward. Satellite time‐series data suggested that, during the peak river discharge time in July with favorable southwest monsoon, the plume area was highly correlated with the river discharge of the same month. Interestingly, the plume area in August was also dominated by the discharge in July. In August, as the direct effect of freshwater discharge weakening, the plume area also became positively correlated with wind speed in the 45° and 60°direction, suggesting that the plume extension was more influenced by the southwesterly wind during periods of smaller discharge. Furthermore, a few special cases with unique plume extensions were found under extreme weather conditions. Finally, we found no significant long‐term trend of plume area change over 1998–2010 in summertime and concluded that the interannual variation was probably regulated by natural variation rather than anthropogenic effects, such as construction of the Three Gorges Dam. This study will have implications for biogeochemical and modeling studies in large river plume areas.