Quantification of multi-source contributions to volume transport in the Tsushima Strait

As the sole channel connecting both the East China Sea and the Yellow Sea to the Sea of Japan, the contribution of specific sources of volume transport in the Tsushima Strait remains unknown. Using the Lagrangian trajectory model TRACMASS, this study identifies the sources of volume transport through the Tsushima Strait and quantifies the contributions from three major pathways: the East Taiwan Channel, the Taiwan Strait, and the Northern Yellow Sea. The model accurately reproduces the persistent quasi-unidirectional current that transports water through the Tsushima Strait into the Sea of Japan throughout the year. The East Taiwan Channel and Taiwan Strait serve as the principal contributors to the Tsushima Strait’s volume transport, accounting for 1.58 Sv (51.8 %) and 1.04 Sv (34.1 %), respectively. However, the Northern Yellow Sea makes a relatively minor contribution of 0.17 Sv (5.7 %). Volume transport through the Tsushima Strait is primarily sourced from the East Taiwan Channel for most of the year, exhibiting bimodal seasonal peaks in April and November driven by intensified Kuroshio shelf intrusion. In contrast, the Taiwan Strait becomes the dominant contributor during August and September, when strengthened transport occurs under the combined influence of the Taiwan Warm Current and monsoon transition. Volume transport from the Northern Yellow Sea to the Tsushima Strait is primarily driven by the Korean Coastal Current. In addition, the runoff and long-resident water masses retained within the East China Sea and the Yellow Sea also serve as supplementary contributors to the transport of Tsushima Strait.