Subtidal variability in the Taiwan Strait induced by combined forcing of winter monsoon and topography
- 9 Downloads
As an important channel connecting the East and South China Seas, circulations in the Taiwan Strait are strongly influenced by the East Asian monsoon and the topography of the strait, especially the Taiwan Bank (TWB), which is a remarkable topographic feature located at the southern entrance to the strait. Based on a series of pressure gauges deployed roughly 40 km offshore along the western Strait, subtidal sea-level variability under the combined impact of winter monsoon and topography was studied. The analyses show significant along-strait coherences of subtidal sea levels and their coherences with the large-scale monsoon wind for periods from 2 to 14 days. It is suggested that these fluctuations are mainly forced waves driven by the large-scale winds. In addition to the normal cross-shore wind setup, a sea-level setup in the along-strait direction is confirmed, which is induced by the combined forcing of the fluctuating winter monsoon and the blocking of the TWB. A southward current surge driven by a northerly wind event will cause a rising sea level over the TWB inducing a southward along-shore slope anomaly to the north of the TWB and a reversed slope anomaly to the south. The subtidal current through the channel to the west of the TWB is found to be influenced by the reversed slope anomalies generated via the along-shore setup.
KeywordsSubtidal variabilities Along-strait sea level setup Taiwan Strait Taiwan Bank
Unable to display preview. Download preview PDF.
This work was supported by National Natural Science Foundation of China (Grant Nos. 41476005 & U1305231). The field work was supported by Chinese Offshore Physical Oceanography and Marine Meteorology Investigation and Assessment Project (Grant No. 908-ZC-I-01).
- Bendat J S, Piersol A G. 1971. Random Data: Analysis and Measurement Procedures. New York: John Wiley & SonsGoogle Scholar
- Chen C K. 1975. A study of the movement of cold fronts and associated precipitation along the coast southeast China. Atmosp Sci, 2: 9–21Google Scholar
- Chen D K, Su J L. 1987. Continental shelf waves study along China coast (in Chinese). Acta Oceanol Sin, 9: 1–15Google Scholar
- Chuang W S. 1985. Dynamics of subtidal flow in the Taiwan Strait. J Oceanogr, 41: 65–72Google Scholar
- Ekman V W. 1905. On the influence of the earth’s rotation on ocean currents. Ark Mat Astron Fys, 2: 1–53Google Scholar
- Li L. 1989. A study of winter subtidal sea level fluctuation in the Taiwan Strait. Acta Oceanol Sin, 11: 275–283Google Scholar
- Li L, Wu B Y. 1989. A Kuroshio loop in South China Sea?—On circulations of the north-eastern South China Sea (in Chinese with English abstract). J Oceanogr in Taiwan Strait, 8: 89–95Google Scholar
- Li L. 1993. A study on winter subtidal sea level fluctuation along the northern coast of the South China Sea (in Chinese with English abstract). Tropic Oceanogr, 12: 52–60Google Scholar
- Shao H, Li Y, Li L. 2011. Sun glitter imaging of submarine sand waves on the Taiwan Banks: Determination of the relaxation rate of short waves. J Geophys Res, 116: C06024Google Scholar
- Shih C F, Shaw P T, Li H W. 1986. Low Frequency sea level fluctuations around Taiwan (in Chinese). Acta Oceanogr Taiwanica, 17: 18–28Google Scholar
- Trowbridge J H, Chapman D C, Candela J. 1998. Topographic effects, straits and the bottom boundary layer. In: Brink K H, Robinson A R, eds. The Sea. New York: John Wiley and Sons. 63–88Google Scholar
- Wang J, Chen C S. 1989. On cold water intrusions in the eastern Taiwan Strait during the cold season (in Chinese with English abstract). Acta Oceanogr Taiwaica, 22: 43–67Google Scholar
- Wang Y H, Chiao L Y, Lwiza K M M, Wang D P. 2004. Analysis of flow at the gate of Taiwan Strait. J Geophys Res, 109: C02025Google Scholar
- Zhao B R, Cao D M. 1987. Wintertime low frequency fluctuations of Chinese coastal sea-level in the Huanghai sea and the East China Sea. Oceanol Limnol Sin, 18: 563–574Google Scholar