Fate of Multiple River Discharges into China Seas

The China Seas (Bohai Sea, Yellow Sea, East China Sea, and South China Sea) receives huge amounts of freshwater discharges from many large rivers, extensions of these river plumes play a key role in transporting the terrestrial materials into the open ocean. As the estuaries of these rivers are close in locations, also owing to the energetic background dynamics such as tide, shelf current, and monsoon in the China Seas, these river plumes could influence each other. While in the past, they were investigated separately by using limited domain models. Here we developed a large-domain model that covered the entire China Seas to investigate the multiple river plumes together. Origins of the diluted water in different areas were identified by releasing passive tracers from these rivers. It was found that in winter season, all these river plumes are confined to the Chinese coast, forming a continuous low-salinity band extending for ~ 4,000 km. While in summer season these river plumes extended offshore separately, which covered a large portion of the China Seas. It was also surprisingly found that the Changjiang River plume can barely penetrate the Taiwan Strait although the downshelf-ward winter monsoon last for ~ 7 months, while the Pearl river plume can travel northward for very long distance to the Tokara and T/K Straits. Quantitative results will be presented.