A climatological description of circulation in and around the East China Sea

To provide baseline information for the biogeochemical studies, the circulation in the three-sea (Bohai, Yellow Sea and East China Sea) system is derived from climatological forcing, using a three-dimensional general circulation model. In the light of extensive literature dealing with similar subjects, the discussion is focused mostly on previously under-represented parts of the circulation, namely, seasonal variations of circulation in the surface layer, Changjiang plume dispersal, sea-level variations, and upwelling–downwelling locations and intensities. In terms of circulation, notable features include the development of China Coastal Current in fall and winter, appearance of a southward coastal jet off the west coast of Korean Peninsula in winter, and northward expansion of Taiwan Warm Current in summer. In response to the seasonally changing circulation, the Changjiang plume dispersal is primarily southward in winter and northeastward in summer. Two upwelling centers near the shelfbreak are worth noting. One is to the northeast of Taiwan and the other is to the southwest of Kyushu. Both are associated with anticyclonic meanders of the Kuroshio Current. Along the Kuroshio axis, a series of upwelling and downwelling centers develops in response to topographic forcing. East of Ryukyu Islands, the model also predicts a persistent upwelling location east of Okinawa Island.