Measurements of volume and heat transport of the surface Kuroshio

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Intensive surveys of the Kuroshio off Shikoku were carried out during 1993-1995 along a subsatellite track of the altimeter satallite TOPEX/POSEIDON.Hydrographic surveys and towed-ADCP (acoustic Doppler current profiler) surveys were carried out repeatedly along the line. Data from those observations as well as moored current measurements were analyzed synthetically. The following results were obtained ;(1) Two modes of the surface Kuroshio were detected by the repeated towed-ADCP surveys : one is the Kuroshio flowing very close to the coast and the other is that flowing far offshore.(2) Very strong flows (up to 100 cm/sec) and very strong vertical shears (stronger than 0.01 sec^<-1>) were observed around 300m depth by a moored-ADCP.(3) Generally, geostrophic shears estimated from the repeated hydrographic survey data compare well with vertical shears obtained from the direct current measurement data, but the abovementioned strong shears were not able to be estimated from the present hydrographic data.(4) Tide gauge data at a coastal station were compared with satellite altimetry data successfully and found to represent well the sea level fluctuations on the coastal side of the Kuroshio.(5) On the basis of combination of those in situ oceanographic data and satellite altimetry data, a three-year long time series of the Kuroshio transport was obtained with ten-day resolution. The results show that there are not apparent seasonal signals in the estimated fluctuations, which fact gives us a very important and interesting task in the future.