长江口及邻近海域夏季温盐分布特征数值分析

Numerical analysis of characteristics of temperature-salinity distributions at the Changjiang Estuary and its adjacent areas in summer

基于EFDC模式建立长江口及邻近海域三维温盐模型,计算中加入径流、风、潮流和太阳辐射,与2005年7月观测资料进行对比验证表明:该文建立的长江口及邻近海域温盐模型可以较好地模拟该海域夏季温盐分布特征变化.由计算结果分析得到,长江口外夏季等温线呈南北走向,近岸高、口外低,长江口夏季水温分布沿着淡水舌方向由口门外逐渐减小;夏季长江冲淡水特征显著,表层低盐水可越过123°E,在长江口外形成向东淡水舌;长江口外冲淡水作用强烈区域的温盐跃层强度最大,其温跃层强度可达0.3℃/m,盐跃层强度可达2/m;长江口外温盐跃层位置重合或接近.

Based on the Environmental Fluid Dynamic Code （EFDC）, a 3-D water temperature and salinity model for the Changjiang Estuary and its adjacent areas was established. River discharge, tide, wind and solar radiation were considered in this model. Compared with the observed data in July 2005, the simulated results were fairly consistent with the observations. It can be analyzed from the results that the temperature isolines off the Changjiang Estuary in summer are along the south-north direction, with high values nearshore and low values offshore; in the Changjiang Estuary, the temperature is descending from the estuary to the offshore along the direction of Changjiang Diluted Water （CDW）. The characteristics of CDW are prominent in summer. The low-salinity surface water can reach out 123° E and has a trend of east expansion off the Changjiang Estuary. The intensities of themocline and halocline are extremely high at the area of CDW, which reach the values of 0.3 ℃/m and 2/m, respectively. The positions of thermocline and halocline are coincident or close-by off the Changjiang Estuary.