Abstract
A 1.5-layer reduced-gravity model forced by wind stress is used to study the bifurcations of the North Equatorial Current (NEC). The authors found that after removing the Ekman drift, the modelled circulations can serve well as a proxy of the SODA circulations on the σ θ =25.0 kg m−3 potential density surface based on available long-term reanalysis wind stress data. The modelled results show that the location of the western boundary bifurcation of the NEC depends on both zonal averaged and local zero wind stress curl latitude. The effects of the anomalous wind stress curl added in different areas are also investigated and it is found that they can change the strength of the Mindanao Eddy (ME), and then influence the interior pathway.
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Cai, S. Q., Liu, H. L., Li, W., and Long, X. M., 2005. Application of LICOM model to the numerical study of the water exchange between the South China Sea and its adjacent oceans. Acta Oceanologica Sinica, 24(4): 10–19.
Chen, Z. H., and Wu, L. X., 2011. Dynamics of the seasonal variation of the North Equatorial Current bifurcation. Journal of Geophysical Research, 116, C02018, Doi: 10.1029/2010-JC006664.
Chu, T. Y., 1972. A study on the water exchange between Pacific Ocean and the South China Sea. Acta Oceanographica Taiwanica, 2: 11–24.
Dale, W. L., 1956. Wind and drift currents in the South China Sea. The Malayan Journal of Geography, 8: 1–31.
Fine, R., Lukas, R., Bingham, F. M., Warner, M. J., and Gammon, R. H., 1994. The western equatorial Pacific is a water mass crossroads. Journal of Geophysical Research, 99: 25 063–25 080.
Gordon, A. L., 1986. Interocean exchange of thermocline water. Journal of Geophysical Research, 91: 5037–5046.
Han, Y. J., 1984. A numerical world ocean general circulation mode1, Part I. Basic design and barotropic experiment. Dynamics of Atmospheres and Oceans, 8: 107–141.
Huang, Q. Z., 1983. Variations of velocity and transport of the kuroshio in the bashi channel. Journal of Tropical Oceanography, 2(1): 35–40 (in Chinese with English abstract).
Johnson, G. C., and McPhaden, M. J., 1999. Interiod pycnocline flow from the Subtropical to the Equatorial Pacific Ocean. Journal of Physical Oceanography, 29: 3073–3089.
Kessler, W. S., and Taft, B. A., 1987. Dynamic height and zonal geostrophic transports in the central Pacific during 1979–84. Journal of Physical Oceanography, 17: 97–122.
Kim, Y. Y., Qu, T. D., Jensen, T., Miyama, T., Mitsudera, H., Kang, H.-W., and Ishida, A., 2004. Seasonal and interannual variations of the North Equatorial Current bifurcation in a high-resolution OGCM. Journal of Geophysical Research, 109, C03040, Doi: 10.1029/2003JC002013.
Li, K. R., Lin, X. C., and Wu, Z. X., 1996. The features of mean wind stress field in the pacific ocean. Acta Geographica sinica, 51(1): 25–32 (in Chinese with English abstract).
Li, L. J., Liu, Q. Y., and Liu, W., 2005. Surface speed and bifurcation of the North Pacific Current in the Pacific ocean. Journal of Ocean University of China, 35(3): 370–374 (in Chinese with English abstract).
Li, L., Nowlin, W. D., and Su, J. L., 1998a. Anticyclonic rings from the Kuroshio in the South China Sea. Deep Sea Research Part I, 45: 1 469–1 482 (in Chinese with English abstract).
Li, W., Liu, Q. Y., and Xu, Q. Y., 1994. The effect of the sst anomaly in the north pacific due to the meander of the kuroshio in winter on the low frequency oscillation. Journal of Ocean University of Qingdao, 24(4): 447–454 (in Chinese with English abstract).
Li, W., Liu, Q. Y., and Yang, H. J., 1998b. Principal features of ocean circulation in the luzon strait. Journal of Ocean University of Qingdao, 28(3): 345–352 (in Chinese with English abstract).
Lighthill, M. J., 1969. Dynamic response of the Indian Ocean to onset of the southwest monsoon. Philosophical Transactions of the Royal Society of London A, 265: 45–92.
Liu, Q. Y., Liu, C. T., Zheng, S. P., Xu, Q. C., and Li, W., 1996. The deformation of Kuroshio in the Luzon Strait and its dynamics. Journal of Ocean University of Qingdao, 26(4): 413–420 (in Chinese with English abstract).
Liu, Q. Y., Pan, A. J., and Liu, Z. Y., 2003. Intraseasonal oscillation and baroclinic instability of upper layer ocean in the north equator current. Oceanologia and limnologia sinica, 34(1): 94–100 ( in Chinese with English abstract).
Liu, Z., 1994. A simple model of the mass exchange between the subtropical and tropical ocean. Journal of Physical Oceanography, 24: 1153–1165.
Lu, P., McCreary, J. P., and Klinger, B. A., 1998. Meridional circulation cell and the source water of the Pacific equatorial undercurrent. Journal of Physical Oceanography, 28: 62–84.
Masumoto, Y., and Yamagata, T., 1991. Response of the Western Tropical Pacific to the Asian Winter Monsoon: The generation of the Mindanao Dome. Journal of Physical Oceanography, 21: 1386–1398.
Masuzawa, J., 1968. Second cruise for CSK, Ryofu Maru, January to March 1968. Oceanographic Magazine, 20: 173–185.
McCreary, J. P., and Lu, P., 1994. On the interaction between the subtropical and equatorial ocean circulation:the Subtropical Cell. Journal of Physical Oceanography, 24: 466–497.
Metzger, E. J., and Hurlburt, H. E., 1996. Coupled dynamics of the South China Sea, the Sulu Sea, and the Pacific Ocean. Journal of Geophysical Research, 101: 12 331–12 352.
Metzger, E. J., and Hurlburt, H. E., 2001. The nondeterministic nature of Kuroshio penetration and eddy shedding in the South China Sea. Journal of Physical Oceanography, 31(7): 1712–1732.
Munk, W. H., 1950. On the wind-driven ocean circulation. Japan Journal of Meteorology, 7: 79–93.
Nitani, H., 1972. Beginning of the Kuroshio. Kuroshio, Physical Aspects of the Japan Current. University of Washington Press, Washington, USA, 129–163.
Qiu, B., and Chen, S., 2010. Interannual-to-decadal variability in the bifurcation of the North Equatorial Current off the Philippines. Journal of Physical Oceanography, 40: 2525–2538.
Qiu, B., and Lukas, R., 1996. Seasonal and interannual variability of the North Equatorial Current, the Mindanao Current, and the Kuroshio along the Pacific western boundary. Journal of Geophysical Research, 101: 12 315–12 330.
Qu, T. D., and Lukas, R., 2002. Depth distribution of the subtropical Gyre in the North Pacific. Journal of Oceanography, 58(3): 525–529.
Qu, T. D., and Lukas, R., 2003. The bifurcation of the North Equatorial Current in the Pacific. Journal of Physical Oceanography, 33: 5–18.
Qu, T. D., Meyers, J. G.., and Godfrey, S., 1997. Upper ocean dynamics and its role in maintaining the annual mean western Pacific warm pool in a global GCM. International Journal of Climatology, 17: 711–724.
Qu, T. D., Mitsuder, A. H., and Yamagata, T., 2000. Intrusion of the North Pacific waters into the South China Sea. Journal of Geophysical Research, 105(c3): 6415–6424.
Qu, T. D., Mitsudera, H., and Yamagata, T., 1998. On the western boundary currents in the Philippine Sea. Journal of Geophysical Research, 103(4): 7537–7548.
Qu, T. D., Mitsudera, H., and Yamagata, T., 1999. A climatology of the circulation and water mass distribution near the Philippine coast. Journal of Physical Oceanography, 29: 1488–1505.
Schott, G., 1939. Die äquatorialen Strömungen des westlichen Stillen Ozeans. Annalen der Hydrographie und Maritimen Meteorologie, 67: 247–257 (in German).
Stommel, H. M., 1948. The westward intensification of wind driven ocean currents. Transactions, American Geophysical Union, 29: 202–206.
Stommel, H., and Yoshida, K., 1972. Bathymetry of the Kuroshio Region. University of Tokyo Press, Tokyo, Janpan, 53–80.
Su, J. L., and Yuan Y. L., 2005. Coastal Hydrology in China. Ocean Press, Beijing, China, 250–296 (in Chinese).
Sverdrup, H. U., 1947. Wind-driven currents in a baroclinic ocean with application to the equatorial currents of the eastern Pacific. Proceedings of the National Academy of Sciences, 33: 318–326.
Takahashi, T., 1959. Hydrographical researches in the western equatorial Pacific. Memoirs of the Faculty of Fisheries, Kagoshima University, 7: 141–147.
Tomoko, I., and Liu Z. Y., 2002. Mid-latitude wind forcing and subduction of temperature anomalies. Journal of Physical Oceanography, 32: 1094–1105.
Toole, J. M., Millard, C., Wang, Z., and Pu, S., 1990. Observations of the Pacific North Equatorial Current bifurcation at the Philippine coast. Journal of Physical Oceanography, 20: 307–318.
Toole, J. M., Zou, E., and Millard, R. C., 1988. On the circulation of the upper waters in the western equatorial Pacific Ocean. Deep Sea Research Part A, 35: 1451–1482.
Tsuchiya, M., 1968. Upper waters of the intertropical Pacific Ocean. Johns Hopkins Oceanographic Studies, 4: 50.
Wajsowicz, R. C., 1999. Variations in gyre closure at the water mass crossroads of the western equatorial Pacific Ocean. Journal of Physical Oceanography, 29: 3002–3024 (in Chinese with English abstract).
Wang, Q. Y., and Hu, D. X., 2006. Bifurcation of the North Equato-rial Current derived from altimetry in the Pacific Ocean. Journal of Hydrodynamics, 18(5): 620–626.
Wang, Q. Y., Cao, R. X., Zhang, S. W., and Hu, D. X., 2009. Surface bifurcation of the NEC in the Pacific Ocean. Science in China (Series D), 39(1): 116–120 (in Chinese).
Wang, Q., and Liu, Q. Y., 2000. The study on the pacidic subtropical cell. The National Science Foundation of China, 1: 1–5 ( in Chinese with English abstract).
Wang, W., and Su, J. L., 1987. A barotropic model about the Kuroshio system and the vortex phenomenon in Yellow Sea and East Sea. Acta Oceanlogica Sinica, 9(3): 271–275 (in Chinese with English abstract).
Webster, P. J., and Lukas, R., 1992. TOGA/COARE: The coupled ocean-atmosphere response experiment. Bulletin of the American Meteorological Society, 73(9): 1377–1416.
Wyrtki, K., 1961. Physical oceanography of the southeast Asian waters. NAGA Report Vol. 2, University of California, 195pp.
Yaremchuk, M., and Qu, T. D., 2004. Seasonal variability of the large-scale currents near the coast of the Philippines. Journal of Physical Oceanography, 34(4): 844–855.
Ye, A. L., and Li, F. Q., 1992. Physical Oceanography. Ocean University of Qingdao Press, Qingdao, China, 684pp (in Chinese).
Yuan, D. L., 2002. Dynamics of the Luzon Strait transports. Acta Oceanologica Sinica, 21(2): 175–185.
Zeng, Q. C., Ji, Z. Z., and Li, R. F., 1985. A numerical offshore current model and dectection. Journal of Hydrodynamics, 2(1): 67–71 ( in Chinese with English abstract).
Zhang, X. D., Xiu, Y. R., Liu, J. F., Su, G., and Wang, Q. Y., 2008. The determination about the NEC and its bifurcation latitude of the variations. Marine Forecasts, 25(2): 33–41 (in Chinese with English abstract).
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Liu, Y., Wang, Q., Song, J. et al. Numerical study on the bifurcation of the North Equatorial Current. J. Ocean Univ. China 10, 305–313 (2011). https://doi.org/10.1007/s11802-011-1840-3
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DOI: https://doi.org/10.1007/s11802-011-1840-3