Japan Sea thermohaline structure and circulation. Part II: A variational P-vector method

Abstract

The second part of this work investigates the seasonal variabilities of the Japan/East Sea (JES) circulation using the U.S. Navy Generalized Digital Environmental Model (GDEM) climatological temperature and salinity dataset (public domain) on a 0.5° × 0.5° grid. A variational P-vector method was developed to invert the velocity field. The GDEM for the JES was built up on historical (1930-97) 136 509 temperature and 52 572 salinity profiles. The climatological mean and seasonal variability of the current systems are well inverted, especially the Tsushima Warm Current and its bifurcation, the East Korean Warm Current (EKWC), the Japan nearshore branch, the confluence of the EKWC, and the North Korean Cold Curent near the Korean coast and flows northeastward along the subpolar front, and a mesoscale anticyclonic eddy in the Ulleng/Tsushima Basin. Furthermore, this method has the capability to invert flow reasonably well across the shallow straits such as the Tsushima/Korea, Tsugaru, and Soya Straits. The GDEM temperature and salinity and the inverted velocity fields provide balanced initial fields for JES numerical modeling and simulation.