Behavior of Warm-Core Rings in a Double-Gyre Wind-Driven Ocean Circulation Model
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Numerical experiments have been performed to understand the movement of warm-core rings in the Kuroshio-Oyashio Transition region, considering the double-gyre ocean circulation represented by a 2.5-layer primitive equation model. Rings, eddies, and frontal disturbances are simulated, and analytical descriptions of warm-core ring behavior are examined. Warm-core rings are usually generated at the south of the zero wind stress curl line (ZWCL), either off-shore or near-shore, and a near-shore ring gradually moves northward along the coast, supplied with energy from the sub-tropical front and other rings. When they approach the ZWCL, two different types of movements occur, which is affected by the intensity of the rings and controlled by the wind stresses. In case the ring intensity is strong, it moves northward along the coast against the subarctic western boundary current system and cold-core rings, whereas a moderate ring is advected by them to the northeastward. The advection process of moderate rings seems to be important for northeastward movement of the Kuroshio warm-core rings in the middle of the Oyashio current system. The mechanism of large-scale forcing dynamics influences the cross-shore location of rings and implications for the fishing ground formation of the Pacific saury are described.
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- Chelton, D. B. and M. G. Schlax (1996): Global observation of oceanic Rossby waves. Science, 272, 234–238.Google Scholar
- Itoh, S. and T. Sugimoto (2001a): Dynamics of long-term northward movement of warm-core rings and their effect on fishing ground formation. Bull. Japan Soc. Fish. Oceanogr., 65, 15–21 (in Japanese with English abstract).Google Scholar
- Kawamura, H., K. Mizuno and Y. Toba (1986): Formation process of a warm-core ring in the Kurohsio-Oyashio frontal zone—December 1981-October 1982. Deep-Sea Res., s11/ 12, 1617–1640.Google Scholar
- Mishra, P. and T. Sugimoto (2000): Formation processes and associated events in the evolution of Kuroshio warm core ring. Proceedings of the PORSEC 2000 Goa, India, Vol. 2, 565–570.Google Scholar
- Yasuda, I. and Y. Watanabe (1994): On the relationship between the Oyashio front and saury fishing grounds. Fish. Oceanogr., 3, 172–182.Google Scholar
- Yasuda, I., K. Okuda and M. Hirai (1992): Evolution of a Kuroshio warm-core ring—variability of the hydrographic structure. Deep-Sea Res., 39, S131–S161.Google Scholar