Abstract
The short-range (one month) variability of the Kuroshio path was predicted in 84 experiments (90-day predictions) using a model in an operational data assimilation system based on data from 1993 to 1999. The predictions started from an initial condition or members of a set of initial conditions, obtained in a reanalysis experiment. The predictions represent the transition from straight to meander of the Kuroshio path, and the results have been analyzed according to previously proposed mechanisms of the transition with eddy propagation and interaction acting as a trigger of the meander and self-sustained oscillation. The reanalysis shows that the meander evolves due to eddy activity. Simulation (no assimilation) shows no meander state, even with the same atmospheric forcing as the prediction. It is suggested therefore that the initial condition contains information on the meander and the system can represent the evolution. Mean (standard deviation) values of the axis error for all 84 cases are 13, 17, and 20 (10, 10, and 12) km, in 138.5°E, in the 30-, 60-, and 90-day predictions respectively. The observed mean deviation from seasonal variation is 30 km. The predictive limit of the system is thus about 80 days. The time scale of the limit depends on which stage in the transition is adopted as the initial condition. The gradual decrease of the amplitude in a stage from meander to straight paths is also predicted. The predictive limit is about 20 days, which is shorter than the prediction of the opposite transition.
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References
Adamec, D. (1989): Predictability of a quasi-geostrophic ocean flow; Sensitivity of varying model vertical resolution. J. Phys. Oceanogr., 19, 1753–1764.
Akitomo, K., T. Awaji and N. Imasato (1991): Kuroshio path variation south of Japan, 1, Barotropic inflow-outflow model. J. Geophys. Res., 96, 2549–2560.
Brasseur, P., E. Blayo and J. Verron (1996): Predictability experiments in the North Atlantic Ocean: Outcome of a quasigeostrophic model with assimilation of TOPEX/POSEIDON altimeter data. J. Geophys. Res., 101, 14161–14173.
Carton, J. A. (1987): How predictable are the geostrophic currents in the recirculation zone of the north Atlantic? J. Phys. Oceanogr., 17, 751–762.
Ebuchi, N. and K. Hanawa (2003): Influences of mesoscale eddies on variations of the Kuroshio path south of Japan. J. Oceanogr., 59, 25–36.
Endoh, T. and T. Hibiya (2000): Numerical study of the generation and propagation of trigger meanders of the Kuroshio South of Japan. J. Oceanogr., 56, 409–418.
Ezer, T. and G. L. Mellor (1994): Continuous assimilation of Geosat altimeter data into a three-dimensional primitive equation Gulf Stream model. J. Phys. Oceanogr., 24, 832–847.
Holland, W. R. and L. B. Lin (1975): On the generation of mesoscale eddies and their contribution to the oceanic general circulation. I. A preliminary numerical experiment. J. Phys. Oceanogr., 5, 642–657.
Hurlburt, H. E., O. M. Smedstad, R. C. Rhodes, J.-F. Cayula, C. N. Barron and E. J. Metzger (2000): A feasibility demonstration of ocean model eddy-resolving nowcast/forecast skill using satellite altimeter data. Naval Research Laboratory Report NRL/MR/7320-00-8235, 23 pp.
Ichikawa, K. (2001): Variation of the Kuroshio in the Tokara Strait induced by meso-scale eddies. J. Oceanogr., 57, 55–68.
Kamachi, M., T. Kuragano, N. Yoshioka, J. Zhu and F. Uboldi (2001): Assimilation of satellite altimetry into a Western North Pacific operational model. Adv. Atmos. Sci., 18, 767–786.
Kamachi, M., T. Kuragano and S. Sugimoto (2003): Present status of assessments of ocean data assimilation products: An introduction to GODAE metrics. Weather Service Bulletin, Japan Meteorological Agency, 70, S107–S122 (in Japanese).
Kamachi, M., T. Kuragano, H. Ichikawa, H. Nakamura, A. Nishina, A. Isobe, D. Ambe, M. Arai, N. Gohda, S. Sugimoto, K. Yoshita, T. Sakurai and F. Uboldi (2004): Operational data assimilation system for the Kuroshio south of Japan: Reanalysis and validation. J. Oceanogr., 60, this issue, 303–312.
Kawabe, M. (1985): Sea level variations at the Izu Islands and typical stable paths of the Kuroshio. J. Oceanogr. Soc. Japan, 41, 307–326.
Kawabe, M. (1995): Variations of current path, velocity, and volume transport of the Kuroshio in relation with the large meander. J. Phys. Oceanogr., 25, 3103–3117.
Kawabe, M. (2003): Study on variations of current path and transport of the Kuroshio. Oceanogr. in Japan, 12, 247–267 (in Japanese).
Kikuchi, H. (1987): A study of Kuroshio variability observed with direct measurements. Master Thesis, Department of Water Civil Engineering, Kyushu University, 109 pp. (in Japanese).
Komori, N., T. Awaji, Y. Ishikawa and T. Kuragano (2003): Short-range forecast experiments of the Kuroshio path variabilities south of Japan using TOPEX/Poseidon altimetric data. J. Geophys. Res., 108, N0. C1, 3010, doi:10.1029/2001JC001282.
Kuragano, T. and M. Kamachi (2000): The global statistical space-time scales of oceanic variability estimated from the TOPEX/POSEIDON altimeter. J. Geophys. Res., 105, 955–974.
Lorenz, E. N. (1982): Atmospheric predictability experiments with a large numerical model. Tellus, 34, 505–513.
Mellor, G. L. and T. Ezer (1991): A Gulf stream model and an altimetry assimilation scheme. J. Geophys. Res., 96, 8779–8795.
Ocean Observing System Development Panel (OOSDP) (1995): Scientific design for the common module of the Global Ocean Observing System and the Global Climate Observing System: An ocean observing system for climate. Dept. of Oceanogr., Texas A & M Univ., College Station, Texas, 265 pp.
Qiu, B. and W. Miao (2000): Kuroshio path variations south of Japan: Bimodality as a self-sustained internal oscillation. J. Phys. Oceanogr., 30, 2124–2136.
Qu, T., H. Mitsudera and B. Qiu (2001): A climatological view of the Kuroshio/Oyashio system east of Japan. J. Phys. Oceanogr., 31, 2575–2589.
Rhodes, R. C., H. E. Hurlburt, A. J. Wallcraft, C. N. Barron, P. J. Martin, E. J. Metzger, J. F. Shriver, D. S. Ko, O. M. Smedstad, S. L. Cross and A. B. Kara (2002): Navy realtime global modeling systems. Oceanography, Special Issue-Navy Operational Models: Ten Years Later, 15, No. 1, 29–43.
Shoji, D. (1972): Time variation of the Kuroshio south of Japan. p. 217–234. In Chapter 7, Kuroshio-Its Physical Aspects, edited by H. Stommel and K. Yoshida, Univ. of Tokyo Press, Tokyo.
Taira, K. and T. Teramoto (1981): Velocity fluctuations of the Kuroshio near the Izu Ridge and their relationship to current path. Deep-Sea Res., 28A, 1187–1197.
Yoon, J.-H. and I. Yasuda (1987): Dynamics of the Kuroshio large meander. Two-layer model. J. Phys. Oceanogr., 17, 66–81.
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Kamachi, M., Kuragano, T., Sugimoto, S. et al. Short-Range Prediction Experiments with Operational Data Assimilation System for the Kuroshio South of Japan. Journal of Oceanography 60, 269–282 (2004). https://doi.org/10.1023/B:JOCE.0000038333.97882.51
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DOI: https://doi.org/10.1023/B:JOCE.0000038333.97882.51