An oceanic current against the wind : how does Taiwan island steer warm water into the East China Sea?
MetadataShow full item record
Along the Taiwan Strait (<100 m in depth) a northeastward flow persists in all seasons despite the annually averaged wind stress that is strongly southwestward. The forcing mechanism of this countercurrent is examined by using a simple ocean model. The results from a suite of experiments demonstrate that it is the Kuroshio that plays the deciding role for setting the flow direction along the Taiwan Strait. The momentum balance along the strait is mainly between the wind stress, friction, and pressure gradient. Since both wind stress and friction act against the northward flow, it is most likely the pressure gradient that forces the northward flow, as noted in some previous studies. What remains unknown is why there is a considerable pressure difference between the southern and northern strait. The Kuroshio flows along the east coast of Taiwan, and thus the western boundary current layer dynamics applies there. Integrating the momentum equation along Taiwan’s east coast shows that there must be a pressure difference between the southern and the northern tip of Taiwan to counter a considerable friction exerted by the mighty Kuroshio. This same pressure difference is also felt on the other side of the island where it forces the northward flow through Taiwan Strait. The model shows that the local wind stress acts to dampen this northward flow. This mechanism can be illustrated by an integral constraint for flow around an island.
Author Posting. © American Meteorological Society, 2007. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 37 (2007): 2563-2569, doi:10.1175/JPO3134.1.
Suggested CitationArticle: Yang, Jiayan, "An oceanic current against the wind : how does Taiwan island steer warm water into the East China Sea?", Journal of Physical Oceanography 37 (2007): 2563-2569, DOI:10.1175/JPO3134.1, https://hdl.handle.net/1912/4157
Showing items related by title, author, creator and subject.
Clay, Peter R.; Longworth, Steven P. (Woods Hole Oceanographic Institution, 1986-10)This report reviews the working principles of the InterOcean S4 electromagnetic current meter and outlines the practical difficulties and engineering solutions to convert these basic principles into a working ...
McCullough, James R. (Woods Hole Oceanographic Institution, 1979-12)When current meters are used to measure mean horizontal currents in surface gravity waves, immunity to the vertical component of flow is important, even though the net vertical flow averages to zero and is normal to the ...
Von Arx, William S. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1950-03)During the past four years a deliberate effort has been made at the Woods Hole Oceanographic Institution to devise methods of kinematic observation generally suited to the needs of oceanographers. One result of this work, ...