摘要
浅海中的密度(σ1)主要是盐度和温度的函数，它随着盐度的增高而增大，随着水温的增高而减小。在空间分布上，靠近大陆沿岸受沿岸水和长江冲淡水的影响，盐度变化较大，密度分布主要决定于盐度分布，而外海盐度变化较小，密度分布就主要决定于温度a。
In this section,the density and spring layer are preliminary analyzed in the investigation area.It is showed from the analysis that the Southern Huanghai Sea area is the lower density one in summer and autumn and thd higher density one in winter and spring. In the Changii-ang River Estuary area, the range of lower density area is the largest in Jnue and the smallest in December. In the south of Jizhou Island, the density is small in summer and autumn than that in winter and spring. The southeast of the investigation area is the high densi-ty one all the year round.It is also showed from the analysis that the strong layer period exists in summer, during this time in the Southern Huanghai Sea, Changjiang River Estuary and the south of Jizhou Islanb,there are not only the spring layer but also the double spring layer and inversion layer. There is not any the sping layer in shallow sea area in winter. The weak spring layer exists in the southeastern deep sea area all the year round.
