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General Session 1: Physical oceanic processes: Dynamics and physical-biological-biogeochemical interactions |
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The off-shore transport of the China Coastal Current over the Taiwan Bank in winter
Tuesday 10th @ 1030-1045
Multi-function Hall
Yuwu Jiang* , State Key Laboratory of Marine Environmental Science, Xiamen University
Lie Yauw Oey, Princeton University, Princeton, New Jersey
Xiao-Hai Yan, College of Earth, Ocean and Environment, University of Delaware
Li Li, Third Institute of Oceanography, State Oceanic Administration, Xiamen, China
Presenter Email: ywjiang@xmu.edu.cn
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| In winter, an off-shore flow of the China Coastal Current (CCC) can be inferred from satellite and in-situ data over the western Taiwan Bank. The dynamics related to this off-shore flow are examined here using observations and model for the first time. Influenced by southward wind stress and opposing pressure gradient, currents over the Taiwan Bank can be classified into three regimes. The southward CCC flows pass the Taiwan Bank when the wind stress is stronger than a critical value which depends on the opposite pressure gradient force. The coastal current turns northward under a weak wind stress. Two opposite currents converge over the bank and a branch of the coastal current then turns into the northward South China Sea Warm Current (SCSWC) during a moderate wind. Analysis of the vorticity balance shows that the off-shore transport is resulted from a negative bottom stress curl which is triggered by a positive vorticity. The positive vorticity is related to a two-flow convergence with a southward CCC attached along the coastline and a northward SCSWC in the shelf. Over the Taiwan Bank, the negative bottom stress curl is reinforced by a gentle slope which enhance this off-shore transport. Composite analyses using observations tend to support the model results. |
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