舟山渔场盐度分布特征分析

The Salinity Distribution in Zhoushan Fishing Ground

利用现场测得的数据,分析了舟山渔场盐度的分布特征。结果如下:渔场外海表层盐度高,分布均匀,近岸盐度低,梯度大。冬季,盐度锋位于渔场近岸,强度强,范围广,走向大致与岸线平行,长江口附近海域有低盐水舌向东伸展;夏季,盐度锋强度减弱,范围缩小,最强处位于30°30'N,122°E附近海域,略呈东北-西南走向。春秋季是盐度锋的消长期。垂直分布上,冬季表层盐度高,随深度增加盐度缓慢增高,近底层略有降低;夏季,表层盐度低,随深度增加盐度迅速增高,至底层又明显降低。春秋季变化和夏季相似,只是秋季表层盐度更低,变化更显著,春季变化相对缓和。

This article analyses the salinity distribution in Zhoushan fishing ground based on-the-spot data. The result is that the surface salinity is higher and more even in open waters than near the shore. In winter, the salinity front is near the shore with strong intensity and wide scope parallel the coast. There is low salinity water tongue which extends towards the east near the mouth of Yangtze River. In summer, the salinity front＇s intensity weakens and the scope reduces. The strongest front is situated 30°30′N 122°E sea area and moves towards northeast-southwest. In spring and autumn, the front grows or declines. In vertical distribution, the surface salinity is high in winter. It rises slowly with the depth increased and decreases slightly near the bottom. In summer, the surface salinity is low. It rises rapid with the depth increased and decreases obviously at the bottom. The change is similar in spring and autumn with in summer. But the surface salinity is lower and changes more obviously in autumn than in spring.