Seasonal variability and the dynamics of Kuroshio intrusion into the Luzon and Taiwan Straits

A fourth-order, fully two-way-coupled duo-grid Pacific Ocean Model (DUPOM) is developed to simulate the regional circulation around Taiwan and Asian Marginal seas. The model uses 1/4° and 1/8° horizontal resolutions for the western and eastern Pacific Ocean domains, respectively. Many important circulation patterns in the Asian Marginal seas are reproduced, including the variations of Kuroshio path; fluctuation of Kuroshio extension; Kuroshio intrusion and retreat through Luzon Strait and over southern East China Sea; formation of a warm core eddy in northern South China Sea in winter; seasonal variation of circulation in Taiwan Strait, etc.. The dynamic of Kurohsio intrusion into the Luzon and Taiwan Straits is further investigated and analyzed. Bottom topography plays an important role on the generation of coastal eddies and their movements. Seasonal Kuroshio intrusion in the Luzon Strait compares well with observations and indicates a possible three layer structure. The throughflow transport variation in the Taiwan Strait is consistent with the field measurements. Our results verify the year round existence of Kuroshio Branch Water (KBW) in the deep portion of the southeast strait.

Acknowledgement: The support from National Science Council, Taiwan (grant number NSC952119M002048) is acknowledged.