A numerical study on the formation of the Yellow Sea Warm Current in winter

Abstract:

The Yellow Sea (YS) is a semi-enclosed marginal sea located between China and the Korean peninsula. The mouth of the YS is open to the East China Sea. The Yellow Sea Warm Current (YSWC) has been shown prominent in winter and previous studies suggest that the main force driving the YSWC is northwesterly winds. The northwesterly wind results in sea level differences between northern and southern areas by decreasing and increasing the sea level respectively in the northern and southern areas. The northward pressure gradient induces the northward intrusion of the YSWC. However, the sensitivity tests of the numerical model used in this study show that the YSWC flows into the YS without northerly winds due to the density difference between the northern fresh water and the southern saline Tsushima Current. Model experiments also show that the northward flow of the YSWC is accelerated by the northerly wind in winter. The model used for the sensitivity test is Regional Ocean Modeling System (ROMS) in the Yellow Sea and the East China Sea. The model grid is 0.1degree horizontal resolution with 40 vertical levels. The sea surface forcing of the model is forced using the European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis data.