Study on the effects of warm eddies induced by the Kuroshioon the physical process of continental shelf region.

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Water motion in the continental shelf region induced by the fluctuation of the Kuroshio was studied by means of satellite picture analysis and numerical experiments. We calculated trajectories of a large number of labeled particles moving in velocity field produced by fluctuating Kuroshio in a numerical barotropic model. When the Kuroshio Flows near the Cape Ashizuri, a large counter-clockwise eddy is produced in the Tosa Bay and particles of the Kuroshio water flow away along the current axis, As it moves offshore form the Cape Ashizuri, those are trapped by the eddy and approach to the coast accompaning with a thermal front. These features in the numerical model were detected in NOAA AVHRR pictures.When and eddy appeares in the Kii-Channel approach, the coastal front in the channel becomes sharper and fluctuates to make a water exchange across the front, These phenomena depend on the density difference of two water masses bounded by the front.Another numerical experiment shows that a pair of eddies is produced by a baroclinic instability of the density front between coastal and oceanic waters on the shelf region, These eddies transport oceanic water toward the coast and coastal water toward the offshore direction across the shear flow such as the Kuroshio, This is the reason why a large parch of low-salinity water mass has been often found in the surface layer of the Kuroshio in summer season (IMASATO and QIU, 1987),