Synoptic fluctuation of the Taiwan Warm Current in winter on the East China Sea shelf

Other literature type, Article English OPEN
J. Xuan ; D. Huang ; T. Pohlmann ; J. Su ; B. Mayer ; R. Ding ; F. Zhou (2017)
  • Publisher: Copernicus Publications
  • Journal: Ocean Science (OS) (issn: 1812-0784, eissn: 1812-0792)
  • Related identifiers: doi: 10.5194/os-13-105-2017
  • Subject: G | GE1-350 | Geography. Anthropology. Recreation | Environmental sciences

The seasonal mean and synoptic fluctuation of the wintertime Taiwan Warm Current (TWC) were investigated using a well-validated finite volume community ocean model. The spatial distribution and dynamics of the synoptic fluctuation were highlighted. The seasonal mean of the wintertime TWC has two branches: an inshore branch between the 30 and 100 m isobaths and an offshore branch between the 100 and 200 m isobaths. The Coriolis term is much larger than the inertia term and is almost balanced by the pressure gradient term in both branches, indicating geostrophic balance of the mean current. Two areas with significant fluctuations of the TWC were identified during wintertime. One of the areas is located to the north of Taiwan with velocities varying in the cross-shore direction. These significant cross-shore fluctuations are driven by barotropic pressure gradients associated with the intrusion of the Taiwan Strait Current (TSC). When a strong TSC intrudes to the north of Taiwan, the isobaric slope tilts downward from south to north, leading to a cross-shore current from the coastal area to the offshore area. When the TSC intrusion is weak, the cross-shore current to the north of Taiwan is directed from offshore to inshore. The other area of significant fluctuation is located in the inshore area between the 30 and 100 m isobaths. The fluctuations are generally strong both in the alongshore and cross-shore directions, in particular at the latitudes 26.5 and 28° N. Wind affects the synoptic fluctuation through episodic events. When the northeasterly monsoon prevails, the southwestward Zhe-Min coastal current dominates the inshore area associated with a deepening of the mixed layer. When the winter monsoon is weakened or the southwesterly wind prevails, the northeastward TWC dominates in the inshore area.
  • References (63)
    63 references, page 1 of 7

    Bai, Y., Pan, D., Cai, W. J., He, X., Wang, D., Tao, B., and Zhu, Q.: Remote sensing of salinity from satellite-derived CDOM in the Changjiang River dominated East China Sea, J. Geophys. Res.- Oceans, 118, 227-243, 2013.

    Bleck, R.: An oceanic general circulation model framed in hybrid isopycnic-Cartesian coordinates, Ocean Model., 37, 55-88, 2002.

    Brink, K. H.: Costal trapped waves and wind-induced currents over the continental shelf, Ann. Rev. Fluid Mech., 23, 389-412, 1991.

    Carnes, M. R.: Description and evaluation of GDEM-V3.0, NRL Rep. NRL/MR/7330-09-9165, Nav. Res. Lab., Washington, D.C., 2009.

    Chen, C., Beardsley, R. C., Limeburner, R., and Kim, K.: Comparison of winter and summer hydrographic observations in the Yellow and East China seas and adjacent Kuroshio during 1986, Cont. Shelf Res., 14, 909-929, 1994.

    Chen, C., Liu, H., and Beardsley, R. C.: An unstructured, finitevolume, three-dimensional, primitive equation ocean model: application to coastal ocean and estuaries, J. Atmos. Ocean. Tech., 20, 159-186, 2003.

    Chen, C., Xue, P., Ding, P., Beardsley, R. C., Xu, Q., Mao, X., Gao, G., Qi, J., Li, C., Lin, H., Cowles, G., and Shi, M.: Physical mechanisms for the offshore detachment of Changjiang Diluted Water in the East China Sea, J. Geophys. Res., 113, C02002, doi:10.1029/2006JC003994, 2008.

    Chen, C. T. A. and Wang, S. L.: Carbon, alkalinity and nutrient budget on the East China Sea continental shelf, J. Geophys. Res.- Oceans, 104, 20675-20686, 1999.

    Chuang, W. S. and Liang, W. D.: Seasonal variability of intrusion of the Kuroshio water across the continental shelf northeast of Taiwan, J. Oceanogr., 50, 531-542, 1994.

    Cui, M., Hu, D., and Wu, L.: Seasonal and intraseasonal variations of the surface Taiwan Warm Current, Chin. J. Oceanol. Limnol., 22, 271-277, 2004.

  • Metrics
    No metrics available
Share - Bookmark