In 1993-1995, in situ oceanographic observations of the Kuroshio south of Japan were carried out,
including direct current measurements and repeated hydrographic surveys along a satellite track of the TOPEX/POSEIDON altimeter.
The velocity field of the Kuroshio is determined by geostrophic calculation using the repeated hydrographic survey data, referenced to velocities observed at mid and abyssal depths.
The volume transports of the Kuroshio estimated from these velocity fields have a high correlation with sea-surface height differences across the Kuroshio.
Having this relationship and using the altimeter data, a time series of the Kuroshio transport was obtained over seven years at ten-day intervals.
Seasonal signal of the Kuroshio transport, excluding contributions by local recirculations, is found to be small compared with that of the Sverdrup transport at mid-latitudes of the North Pacific.
|