Upper-Layer Circulation in the South China Sea

Tangdong Qu International Pacific Research Center, SOEST, University of Hawaii at Manoa, Honolulu, Hawaii

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Abstract

Upper-layer circulation is investigated by using all available historical temperature profiles combined with climatological temperature–salinity relationships in the South China Sea. Two cyclonic eddies are revealed: one is located east of Vietnam (called the East Vietnam eddy) and the other is off northwest Luzon (called the West Luzon eddy). Both local Ekman pumping and remotely forced basin-scale circulation are important mechanisms controlling these two eddies. The Luzon Strait transport (relative to 400 db) is estimated to be of the order 3.0 Sv (1 Sv = 1 × 106 m3 s−1) in the mean, and has a seasonal cycle dominated by the annual signal, with a maximum (5.3 Sv) in January–February and a minimum (0.2 Sv) in June–July. Pressure gradients are also examined to explore the dynamics of the intrusion of waters from the Pacific into the South China Sea through the Luzon Strait.

Corresponding author address: Dr. Tangdong Qu, IPRC–SOEST, University of Hawaii at Manoa, 2525 Correa Road, Honolulu, HI 96822.

Email: tangdong@soest.hawaii.edu

Abstract

Upper-layer circulation is investigated by using all available historical temperature profiles combined with climatological temperature–salinity relationships in the South China Sea. Two cyclonic eddies are revealed: one is located east of Vietnam (called the East Vietnam eddy) and the other is off northwest Luzon (called the West Luzon eddy). Both local Ekman pumping and remotely forced basin-scale circulation are important mechanisms controlling these two eddies. The Luzon Strait transport (relative to 400 db) is estimated to be of the order 3.0 Sv (1 Sv = 1 × 106 m3 s−1) in the mean, and has a seasonal cycle dominated by the annual signal, with a maximum (5.3 Sv) in January–February and a minimum (0.2 Sv) in June–July. Pressure gradients are also examined to explore the dynamics of the intrusion of waters from the Pacific into the South China Sea through the Luzon Strait.

Corresponding author address: Dr. Tangdong Qu, IPRC–SOEST, University of Hawaii at Manoa, 2525 Correa Road, Honolulu, HI 96822.

Email: tangdong@soest.hawaii.edu

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  • Chao, S.-Y., P.-T. Shaw, and S. Y. Wu, 1996: El Nino modulation of the South China Sea circulation. Progress in Oceanography, Vol. 38, Pergamon, 51–93.

  • Chu, P. C., Y. Chen, and S. Lu, 1998: Wind-driven South China Sea deep basin warm-core/cool core eddies. J. Oceanogr.,54, 347–360.

  • Godfrey, J. S., 1989: A Sverdrup model of the depth-integrated flow for the world ocean allowing for island circulations. Geophys. Astrophys. Fluid Dyn.,45, 89–112.

  • He, Y., C. Guan, and H. Gao, 1996: Water temperature and circulation structure in the upper ocean of the northern South China Sea (in Chinese). Acta Oceanol. Sinica,6, 60–69.

  • Hellerman, S., and M. Rosenstein, 1983: Normal monthly wind stress over the world Ocean with error estimates. J. Phys. Oceanogr.,13, 1093–1104.

  • Levitus, S., 1982: Climatological Atlas of the World Oceans. NOAA Prof. Paper No. 13. U.S. Govt. Printing Office, 173 pp.

  • Metzger, E. J., and H. E. Hurlburt, 1996: Coupled dynamics of the South China Sea, the Sulu Sea, and the Pacific Ocean. J. Geophys. Res.,101, 12 331–12 352.

  • Meyers, G., R. J. Bailey, and A. P. Worby, 1995: Geostrophic transport of Indonesian Throughflow. Deep-Sea Res.,42, 1163–1174.

  • Nitani, H., 1972: Beginning of the Kuroshio. Kuroshio: Its Physical Aspects of the Japan Current, H. Stommel and K. Yoshida, Eds., University of Washington Press, 129–163.

  • Oberhuber, J. M, 1988: An atlas based on the “COADS” data set: The budgets of heat, buoyancy and turbulent kinetic energy at the surface of the global ocean. Max-Planck-Institut für Meteorologie Rep. 15. [Available from Max-Planck-Institut für Meteorologie, Bundesstrasse 55, D-20146 Hamburg, Germany.].

  • Qu, T., H. Mitsudera, and T. Yamagata, 1998: On the western boundary currents in the Philippine Sea. J. Geophys. Res.,103, 7537–7548.

  • ——, ——, and ——, 1999: A climatology of the circulation and water mass distribution near the Philippine coast. J. Phys. Oceanogr,29, 1488–1505.

  • ——, ——, and ——, 2000: The intrusion of the North Pacific waters into the South China Sea. J. Geophys. Res.,105, 6415–6424.

  • Shaw, P.-T., and S.-Y. Chao, 1994: Surface circulation in the South China Sea. Deep-Sea Res.,41, 1663–1683.

  • ——, ——, K.-K. Liu, S.-C. Pai, and C. T. Liu, 1996: Winter upwelling off Luzon in the northeast South China Sea. J. Geophys. Res.,101, 16 435–16 448.

  • ——, ——, and L.-L. Fu, 1999: Sea surface height variations in the South China Sea from satellite altimetry. Oceanol. Acta,22, 1–17.

  • Wu, C.-R., P.-T. Shaw, and S.-Y. Chao, 1998: Seasonal and interannual variations in the velocity field of the South China Sea. J. Oceanogr.,54, 361–372.

  • Wyrtki, K., 1961: Physical oceanography of the Southeast Asian waters. Naga Rep. 2, 195 pp. [Available from Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093.].

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