Volume, heat, and salt transport connections between the Taiwan, Cheju, and Korea Straits

Abstract

AB: The main currents flowing into the East China Sea and ultimately the Yellow and the Japan/East Sea are the Kuroshio, entering through the passage between Taiwan and the southwestern tip of the Ryuku Islands, and the Taiwan Warm Current, entering through the Taiwan Strait from the South China Sea. Insight into the circulation of the East China Sea and origin of the Tsushima current are investigated through direct, concurrent measurements of velocities through the Taiwan, Cheju, and Korea Straits. Current data are obtained from six bottom-mounted acoustic Doppler current profilers (ADCPs) arrayed along a section spanning the Korea Strait, a single bottom-moored ADCP in the Cheju Strait, and four bottom-moored ADCPs along a section spanning the Taiwan Strait. Mass transports are computed for the October to December, 1999 time period. In addition, heat and salt transports are examined in conjunction with climatological values of temperature and salinity. Average volume transport is 0.14 Sverdrups (Sv) through the Taiwan Strait, 0.59 Sv for the Cheju Strait, and 3.17 Sv for the Korea Strait. Salt and heat transport through the Korea Strait and into the Japan/East Sea are $ 110.48 x 10^6 kg/s$ and $0.24 x 10^{15}$ watts (w), respectively. The bulk of flow through the Korea Strait must come from the Kuroshio flowing onto the shelf since the flow through the Taiwan Strait (0.14 Sv) is quite small. Some heat loss occurs in the Korea Strait but most of the Kuroshio heat loss occurs in the East China Sea at a rate of about 200 w/$m^2$, and little heat is lost in the Yellow Sea. The total volume transport through the Korea Strait is formed from Taiwan Warm Current and Kuroshio waters which may have been modified by Yellow Sea, East China Sea, and South China Sea waters, and by river outflows. The main source for the Tsushima Current and its flow into the Japan/East Sea is clearly the Kuroshio for this time period.