Slope-Current fluctuations northeast of Taiwan winter 1990

During the winter of 1990, two current-meter moorings were deployed in the outer shelf region across a canyon northeast of Taiwan. The data indicate that a steady flow exists in the southward, along-slope direction, opposite to the nearby northward-flowing Kuroshio current. Tides run transverse to the mean flow. Fluctuations in subtidal current mostly occur on the south side of the canyon, concentrated in the synoptic (2–4 days) band and oriented in the cross-slope direction. From the nearby winds and coastal sea-level observations, it is clear that the rotating-wind field associated with the passage of winter cold front is responsible for generating the observed energetic fluctuations. The northeasterly monsoon wind is very effective in piling up water against the northern coast of Taiwan and establishing an out-flowing geostrophic current. Trailing wind behind the high-pressure system has exactly the opposite effect. The investigation suggests that due to the winter-weather pattern, the area northeast of Taiwan is an important region for water exchange between the East China Sea and the Kuroshio.