Transports and tidal current estimates in the Taiwan Strait from shipboard ADCP observations (1999–2001)

Tidal and mean flows in the Taiwan Strait are obtained from analysis of 2.5 years (1999–2001) of shipboard ADCP data using a spatial least-squares technique. The average tidal current amplitude is 0.46 ms 1, the maximum amplitude is 0.80 ms 1 at the northeast and southeast entrances and the minimum amplitude is 0.20 ms 1 in the middle of the Strait. The tidal current ellipses derived from the shipboard ADCP data compare well with the predictions of a high-resolution regional tidal model. For the mean currents, the average velocity is about 0.40 ms 1. The mean transport through the Strait is northward (into the East China Sea) at 1.8 Sv. The transport is related to the along Strait wind by a simple regression, transport (Sv)=2.42+0.12 wind (ms 1). Using this empirical formula, the maximum seasonal transport is in summer, about 2.7 Sv, the minimum transport is in winter, at 0.9 Sv, and the mean transport is 1.8 Sv. For comparison, this result indicates that the seasonal amplitude is almost identical to the classical estimate by Wyrtki (Physical oceanography of the southeast Asian waters, scientific results of marine investigations of the South China Sea and Gulf of Thailand, 1959–1961. Naga Report 2, Scripps Institute of Oceanography, 195 pp.) based on the mass balance in the South China Sea, while the mean is close to the recent estimate by Isobe [Continental Shelf Research 19 (1999) 195] based on the mass balance in the East China Sea.