Repeat meridional survey of the western North Pacific subtropical gyre by a VOS ADCP during 1997 to 1998

During 1997 to 1998, near-surface currents in the western North Pacific sub tropical gyre have been measured repeatedly by an ADCP mounted on the huli of the volunteer observing ship (VOS) operated mainly between Japan and Aus tralia. The Kuroshio Current, the Kuroshio Recirculation and the North Equa torial Current are clearly identified as two-year mean currents in the lati tude belt 10-34.5 degrees N. Current variability was dominated by baroclini c Rossby waves or mesoscale eddies over the 10-30 degrees N belt except in the latitude belt 13-17 degrees N where the north-to-south shifts of the No rth Equatorial Current stream axis may dominate current variability. The en ergy of the mesoscale variability was concentrated to form large peaks arou nd 18.5 degrees N and 23 degrees N.