The hydrographic and circulation properties of both the Yellow and East China Seas are controlled by their proximity to the Kuroshio Current and the seasonal variation of the monsoon winds. The chief currents are a northwest trending branch of the Kuroshio called the Yellow Sea Current (or Yellow Sea Warm Current), the southward flowing China Coastal Current, and an unnamed current flowing southward along the west coast of Korea that carries low salinity water from the Bohai Gulf. Frontal regions separate the currents in this alternating flow pattern which is identifiable through the year, although the flow strength of the individual currents varies seasonally with the monsoons.
In the winter, strong northerly winds and cold, dry continental air vertically homogenize most of the Yellow and Bohai Seas. The winds also excite subtidal sea level fluctuations that propagate southward along the west coast of the sea all the way to the South China Sea. In the summer, solar forcing and weak wind mxing warm the upper part of the water column, leaving a conspicuous bottom pool of cold water called the Yellow Sea Cold Water, which is formed from the remnant winter water. The stratification usually appears in April and disappears in November. See Tomczak and Godfrey (1994), Guan (1994), Hu (1994), Jilan (1998) and Teague et al. (1998).