The SSH images of TOPEX/POSEIDON (gridded data provided by Kuragano) indicate successive propagation of anticyclonic and cyclonic eddies from the Kuroshio Extension that seem to influence the Kuroshio upstream.
Click on image for 5-day interval animations from 1993 to 1998 (image size 10 MB).
The images from TOPEX/POSEIDON indicate that westward propagating anticyclonic eddies may trigger a short-term meander of the Kuroshio. The sequence shown below resembles the result of the numerical experiment conducted in this study.
The anticyclonic eddy approaches the Kuroshio offshore Kyushu (day 100, 1998); it is advected dowstream where it triggers the meander between the Kii-Peninsula and the Izu Ridge (day 180 to 200, 1998).
The eddy detaches from the Kuroshio and the meander relaxes (day 240).
The detached eddy moves westward meeting the Kuroshio at higher latitudes than the first encounter (day 270), circles clockwise along the Kuroshio, and causes a second meander (day 300).
The structure of the anticyclonic eddies that caused the short-term meander shown above and also the one in 1992, were seen in various in-situ observations: a) ADCP (TOLEX: Tokyo-Ogasawar Line Experiment) time series; b) ADCP north-south section (1991, October); c) XBT north-south temperature section (1991, September). A large eddy was observed in October 1997, and an anticyclonic eddy of similar size was observed during 1991 from September through October along the TOLEX section.
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image to view enlarged figures.