Kuroshio-induced cold eddy streets in the lee of isolated islands

Cold eddy streets formed in the lee of isolated islands were investigated in relation to the Kuroshio current. Multi- temporal SAR images acquired over a one-month period revealed island wake patterns, such as meandering disturbances and eddy streets. These patterns corresponded to the Kuroshio path, indicating a Kuroshio-island interaction. We constructed high-spatial-resolution sea-surface temperature (SST) images for the time when the Kuroshio impinged on the islands by regressing the LANDSAT infrared images on the AVHRR-derived SST. The images revealed low-SST island wakes, some of which included cold eddy streets. A numerical simulation was performed to investigate their formation mechanism. The simulation qualitatively reproduced the cold eddy pattern, with eddy-driven mixing developing a mixed layer down to 100 m, causing the low- SST island wakes. The shedding frequency and distance of the model-produced eddies were close to those of the Karman vortex theory, suggesting that Karman-like cold eddy streets developed behind the islands when the Kuroshio passed.