Southward recirculation of the East China Sea Kuroshio west of Okinawa Island

The surface current of the Kuroshio recirculation region in the East China Sea is investigated. The surface currents in the west of Okinawa Island observed by HF radars and the assimilation results of the Japan Coastal Ocean Predictability Experiment (JCOPE) are analyzed. It appeared that currents in the easternmost edge of the Kuroshio bifurcate southward and flow into the west of Okinawa Island from JCOPE data. The currents are called Kuroshio southward recirculation currents. The currents are controlled by the bottom topography. The wind stress curl in the area where the bifurcated current can be seen in JCOPE data is negative, while the curl is positive in the eastern portion of the Kuroshio. The Kuroshio southward recirculation currents are sometimes enhanced, and their enhancement coincides with that of the positive and negative wind stress curls.