Upper-ocean currents around Taiwan

Current velocity, measured by Shipboard Acoustic Doppler Current Profiler (Sb-ADCP) during 1991-2000, was used to study the upper-ocean (<300m) currents around Taiwan. The collected data were debugged, calibrated, grid, and averaged to compose a three-dimensional current-velocity distribution. The validity of the composite current velocity was supported by 12 sets of moored current-velocity time series. Qualitative agreement was obtained. The moored time series also indicated that the seasonal variation of current around Taiwan was generally weak except for the shallow-water regimes. The composite and moored currents revealed a branch of the Kuroshio that intruded steadily and persistently into the South China Sea. Part of the intruded Kuroshio flowed out of the South China Sea through the northern Luzon Strait and re-united with the main stream Kuroshio. The Kuroshio had two velocity maximum cores southeast of Taiwan, but gradually combined into one as the Kuroshio flowed north. The Kuroshio was deflected by the I-Lan Ridge east of Taiwan and the zonal-running shelf break northeast of Taiwan. At the shelf break, the Kuroshio split, with one branch intruding onto the shelf. West of the Luzon Strait, the Kuroshio intruded into the South China Sea. Some water flowed northward into the Taiwan Strait and re-joined the Kuroshio. Currents in the Taiwan Strait flowed primarily in a northward direction, except for the southward current near the coast of Mainland China. North of the Taiwan Strait, a branch of the northward flow followed the northern coast of Taiwan to join the Kuroshio. The composite current varied consistently from season to season. There was generally poor correlation between currents and local winds, especially in the deep-water regime. Remote forces were important in the currents around Taiwan. (C) 2003 Elsevier Science Ltd. All rights reserved.