Peter C. Chu, Jian Lan, and Hilbert Strauhs
Naval Postgraduate School, Monterey, CA 93943
The seasonal variability of the Japan/East Sea (JES) circulation was studied numerically using the Princeton Ocean Model (POM) with horizontal resolution varying from 11.54 to 18.53 km and 15 sigma levels conforming to a relatively realistic bottom topography. The model was integrated using climatological monthly mean wind stresses, heat and salt fluxes as surface forcing and observational oceanic inflow/outflow at open boundaries. The seasonally averaged effects of isolated forcing terms are presented and analyzed from the following experiments: 1) non-linear effects removed, 2) no lateral transport at open boundary, and 3) wind effects removed. Major currents are simulated reasonably well compared to observations. The nonlinear advection does not affect the general circulation pattern evidently, but does affect the formation of the mesoscale eddies, especially the Ulleung/Tsushima Basin (UTB) eddy (all seasons) and the Japan Basin (JB) cyclonic gyre (spring). The lateral boundary forcing enhances (weakens) the JES volume transport in the summer (winter). The wind forcing is the most important factor (80%) for generating the JB cyclonic gyre. Besides, it drives the Liman Current and damps the East Korean Warm Current in the winter, and generates the UTB eddy, and eddies along the Japan Nearshore Branch (JNB) in all seasons. However, it has almost no effect on the JNB currents for all seasons.