The Xiamen Symposium on Marine Environmental Sciences (XMAS 2025)

105 / 2024-09-08 16:51:36

Dispersal of the Changjiang River water in East Asian shelf seas

Changjiang River plume,Water age,Taiwan Warm Current,water transport

River plumes play a crucial role in the transport of terrestrial materials from rivers to oceans. Knowledge gaps, however, still exist in understanding the far-field transport and ultimate fate of riverine water in coastal oceans. This study conducted a 50-year climatological numerical simulation to investigate the long-term transport processes of Changjiang River water in the East Asian shelf seas. In addition to the distinct seasonality near the estuary and in the coastal area south of the estuary, the Changjiang River water has a trend of accumulation in the shelf seas, which affects the far-field transport of the water. It takes less than a year for the river water to reach the northeastern edge of the East China Sea, over 10 years to enter the Bohai Sea and to cross the South China Sea, reaching the Kalimantan Strait. Kuroshio hinders the cross-shelf transport of Changjiang River water, with the water residing in the Kuroshio region for over six years. The Taiwan Warm Current not only acts as a barrier that regulates the pathways of Changjiang River water but also serves as an important conduit for water leaving the East China Sea. The Changjiang River water leaves the estuary through four branches and forms eight major transport pathways in the Yellow and East China Seas. Approximately 85% of Changjiang River water flows through the Tsushima/Korea Strait, about 14% exits from the shelf edge of the East China Sea, and less than 1% passes through the Taiwan Strait. The results highlight the importance of riverine water renewal and shelf circulation in the long-term transport of river water in coastal oceans.