Intra-seasonal variation of the Kuroshio southeast of Taiwan and its possible forcing mechanism
The intra-seasonal variation of the Kuroshio southeast of Taiwan has been studied using satellite data and a numerical model. Superimposed with the main stream of the Kuroshio, two intra-seasonal signals are revealed in the study region. The fluctuation with a period of 1–6 months results from offshore eddies. The westward propagating cyclonic eddies can reduce or reverse the northward flow east of the Kuroshio between 121° and 123° E, but only slightly touch the core velocity of the Kuroshio. The fluctuation with a period of 2–4 weeks is only significant between Taiwan and the Lan-Yu Island (the low-velocity region). Different mechanisms are responsible for the fluctuation in the low-velocity region in different seasons. In winter, the change of negative wind stress curl in the northeastern South China Sea modulates the circulation southeast of Taiwan, while the typhoon-induced intense wind is responsible for the current fluctuation in summer.
KeywordsIntra-seasonal variation Kuroshio southeast of Taiwan
The valuable comments given by Dr. Yasumasa Miyazawa of JAMSTEC, and the reviewers greatly improved both science and the presentation. Authors YCH and CRW were supported by the National Science Council, Taiwan, ROC, under grants NSC 98-2811-M-003-012 and NSC 98-2628-M-003-001. T. Qu was supported by the National Science Foundation through grant OCE06-23533 and by the JAMSTEC, the NASA, and the NOAA through their sponsorship of the International Pacific Research Center (IPRC). SOEST contribution number 7925 and IPRC contribution number IPRC-690.
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