Japan Coastal Ocean Predictability Experiment Research Articles

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.

CHARACTERISTICS OF WINTER CURRENT PATTERN IN THE ISHIKARI BAY

The winter current pattern in 2003 in the Ishikari Bay was investigated by using the Princeton Ocean Model (POM) and field observation data. The model was forced by six hour, spatially distributed wind and open boundary forcing. The later was obtained from larger scale model namely Japan Coastal Ocean Predictability Experiment (JCOPE). Through three numerical experiments with different driving forces the following conclusions have been deduced: (1) the open boundary forcing is the major driving force for current in deep water, the effect of wind in this region is limited in few surface layers (2) the flow along the shelf and current in shallow region are mainly driven by wind forcing (3) circulations occur in the shallow area during strong wind conditions. A comparison between observed and computed current velocities showed that the model is capable to reproduce current pattern in the bay.