Analysis of hydrographic features and circulation situation in the southern Huanghai Sea in early spring

Hydrographic features and circulation situation in the southern Huanghai Sea (SHS) are studied on the basis of the data obtained by China-Korea Joint Investigation of Ocean Circulation Dynamics in the SHS in the early spring of 1996,The main results are as follows:(1) The temperature-salinity characteristics and the basic circulation pattern in the SHS in the early spring are basically similar to those in winter revealed in the past,However,it is found in this investigation that the axis of the warm water tongue in the middle Huanghai Sea is obviously to the east as compared with wintertime situation and a small-range isolated water body with relatively high temperature and salinity appears in this region,Meanwhile,a middle-layer cold water and a surface inversion layer occur in the local regions of the SHS; (2) the results of direct current measurements not only verify the basic pattern of the circulation showing by temperature-salinity distributions,but also reveal much better some new phenomena occurring in the current field,especially the current around Cheju-do; (3) the Huanghai Warm Current water is a mixture of the Tsushima Warm Current water and the continental shelf water and originates mainly from the frontal region west of Cheju-do.