The study of the temporal and spatial characteristics of western boundary current East of Ruykyu submarne ridge and the transport of Kuroshio in East China Sea

Kuroshio in the East China Sea(KECS)and the currents in the east of the Ryukyu Islands are investigated by analyzing the up-to-date reanalysisdataof the high resolution ocean model.It is found that there is a western boundary current in the east of Ryukyu Islands with a maximum core velocity of 0.2 m/s at 600~1 200 m over the shelf slop.Because the water exchange through the ocean trough in the southwest of Okinawa Island can affect the transport of KECS,the mean transport of KECS steadily increases from south to north,which is 28×106~35×106 m3/s;the transport of the western boundary current in the east of Ryukyu Islands is less an order of magnitudethan that of KECS,whose mean value is less than the standard deviation;because of the current through the ocean trough in the southwest of Okinawa,the transport in the east of Okinawa is less than that in the east of Amami-ohshima.The Rossby wave propagating westward in the east of Ryukyu Islands could influence the western boundary current in the east of Ryukyu Islands distinctly,so the distinct period of the transport of the western boundary current in east of Ryukyu Islands is approximately 100 d.The KECS in the south of the ocean trough is mainly controlledby the Kuroshio in the east of Taiwan,so the period of its transport is also approximately 100 d.But the KESC in the north of the ocean trough does not have thisfeature.