Estimation of freshwater transport and dispersal pathway discharged from the Changjiang River in the East China Sea

We examine the offshore transport and dispersal pathway of the freshwater discharged from the Changjiang River in the East China Sea (ECS) using an interannual simulation of regional ECS model with ROMS. Atmospheric forcing is obtained from the NCEP reanalysis-II 6-hourly data from 1995 to 2005: 10 m wind, temperature, surface pressure and radiation. Surface fluxes of momentum and heat are calculated using bulk formulations. The KPP parameterization is also used. Comparison between the results of 1996 and 1998 clearly demonstrates that the summer monsoon winds play a critical role in spreading freshwater offshore and determining the structure and pathway of the freshwater in the ECS. Analysis of the hindcast simulation also shows that a northeastward freshwater pathway to Jeju Island across the northwestern shelf of the ECS, dominates during the summer period due to the along-shore wind. On the other hand, there is virtually no relationship between the amount of discharge from the Changjiang River and the freshwater transport toward Jeju Island. The analysis also suggests that relatively weak along-shore wind allows an additional pathway to the central region of the ECS along the ambient current between the Taiwan and Korea/Tsushima Straits.


Jae-Hong Moon*1, Naoki Hirose1 and Ig-Chan Pang2

1 Research Institute for Applied Mechanics, Kyushu University, Kasuga-Koen, Kasuga 816-8580, Japan

2 Department of Oceanography, Cheju National University, Jeju 690-756, Korea