Abstract
We examined the surface current structure in the Tsushima Warm Current (TWC) region of the Japan Sea based on a dataset from satellite-tracked surface drifters, including our new deployments during 2004–2008. The gridded mean current velocity and mean kinetic energy (KE) fields calculated from all available drifter data revealed the structure and seasonality of the three branches of the TWC. By comparing the eddy kinetic energy (EKE) field to the KE field, we found four regions where the ratio of EKE to KE was high. In particular, this ratio became extremely high east of the Oki Islands located between the first branch of the TWC (FBTWC) and the second branch of the TWC (SBTWC). Our analysis suggests that the generation of alternate warm and cold eddies east of the Oki Island induced this high ratio. The occurrence of a warm or cold eddy was related to the route—either nearshore or offshore—of the SBTWC. When the offshore route of the SBTWC became dominant, a warm eddy was frequently generated east of the Oki Islands. In contrast, when the nearshore route of the SBTWC became dominant, a cold eddy was more likely to be generated.
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Hansen, D. V. and P.-M. Poulain (1996): Quality control and interpolations of WOCE-TOGA drifters data. J. Atmos. Oceanic Technol., 13, 900–909.
Hase, H., J.-H. Yoon and W. Koterayama (1999): The current structure of the Tsushima Warm Current along the Japan Coast. J. Oceanogr., 55, 217–235.
Isobe, A., M. Ando, T. Watanabe, T. Senjyu, S. Sugihara and A. Manda (2002): Freshwater and temperature transports through the Tsushima-Korea straits. J. Geophys. Res., 107, doi:10.1029/2000JC000702.
Isoda, Y. (1994): Warm eddy movements in the eastern Japan Sea. J. Oceanogr., 50, 1–15.
Japan Sea National Fisheries Research Institute (2004–2008): Report of the Fisheries and Oceanographic Conditions in the Japan Sea (Nihonkai Gyojyo-Kaikyo Sokuhou; https://doi.org/jsnfri.fra.affrc.go.jp/Physical/sokuho.html), No. 588–629.
Katoh, O. (1994): Structure of the Tsushima Current in the southwestern Japan Sea. J. Oceanogr., 50, 317–338.
Katoh, O., K. Morinaga, K. Miyaji and K. Teshima (1996): Branching and joining of the Tsushima Current around the Oki islands. J. Oceanogr., 52, 747–761.
Kurita, Y., M. Matsuyama and T. Senjyu (1999): Topographic eddies east of the Oki Islands in the Japan Sea. Umi to Sora, 75, 13–20.
Lee, D.-K. and P. P. Niiler (2005): The energetic surface circulation patterns of the Japan/East Sea. Deep-Sea Res. II, 52, 1547–1563.
Lee, D.-K., P. P. Niiler, S.-R. Lee, K. Kim and H.-J. Lie (2000): Energetics of the surface circulation of the Japan/East Sea. J. Geophys. Res., 105, 19561–19573.
Matsuyama, M., Y. Kurita, T. Senjyu, Y. Koike and T. Hayashi (1990): The warm eddy observed east of Oki Islands in the Japan Sea (2). Umi to Sora, 66, 67–75 (in Japanese with English abstract).
Morimoto, A. and T. Yanagi (2001): Variability of sea surface circulation in the Japan Sea. J. Oceanogr., 57, 1–13.
Naganuma, K. (1977): The oceanographic fluctuations in the Japan Sea. Kaiyo Kagaku, 9, 139–141 (in Japanese with English abstract).
Ohshima, K. I. (1994): The flow system in the Japan Sea caused by a sea level difference through shallow straits. J. Geophys. Res., 99, 9925–9940.
Senjyu, T., H. Enomoto, T. Matsuno and S. Matsui (2006): Interannual salinity variations in the Tsushima Strait and its relation to the Changjiang discharge. J. Oceanogr., 62, 681–692.
Takematsu, M., Z. Nagano, A. G. Ostrovskii, K. Kim and Y. Volkov (1999): Direct measurements of deep current in the Northern Japan Sea. J. Oceanogr., 55, 207–216.
Toba, Y., K. Tomizawa, Y. Kurasawa and K. Hanawa (1982): Seasonal and year-to-year variability of the Tsushima-Tsugaru current system with its possible cause. La mer, 20, 41–51.
Watanabe, T., O. Katoh and H. Yamada (2006): Structure of the Tsushima Warm Current in the northeastern Japan Sea. J. Oceanogr., 62, 527–538.
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Watanabe, T., Simizu, D., Nishiuchi, K. et al. Surface current structure of the Tsushima Warm Current region in the Japan Sea derived by satellite-tracked surface drifters. J Oceanogr 65, 791–801 (2009). https://doi.org/10.1007/s10872-009-0066-0
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DOI: https://doi.org/10.1007/s10872-009-0066-0