The “von Karman vortex street” to the west of Big Island

Satellite-tracked drifting buoy data and altimetry data are used to study the active vortex field to the west of Big Island.A pair of vortexes were observed at the trajectory of buoy in 1995.The westward propagation of the vortex pair is studied in detail by reproducing the loops of each vortex.The orbital period and radius of the pair of vortex are determined to be 10-11 d and 58-68 km.Two arrays of contra-rotating vortices are displayed in the average sea surface height anomaly(SSHA) field to the west of Big Island.Based on the calculation of the fluid dynamical parameter,the "von Karman vortex street" is proved to be generated to the west of Big Island as the North Equatorial Current impinges upon Big Island from the east.Finally,the analysis of the buoy trajectories in a decade contributes to the conclusion of the pattern of VKVS in a statistical view.