舟山渔场及其邻近海域水团的季节特征

根据2001年夏季和2002年冬季两次现场调查所收集的CTD和营养盐资料,利用模糊聚类分析法,对舟山渔场及其邻近海域水团的季节特征进行了分析.结果表明,舟山渔场及其邻近海域水团的配置、分布范围、温盐特性和营养盐含量都有明显的季节特征.其中,冬季在全海域共有3个水团(江浙沿岸水、台湾暖流表层水和黄海混合水),而夏季则存在4个水团(江浙沿岸水、台湾暖流表层水、台湾暖流深层水和黄海混合水);冬季,江浙沿岸水的分布范围较小,温度偏低,盐度略高,营养盐偏高,而夏季,其分布范围较大,温度偏高,盐度偏低,营养盐偏低;冬季,台湾暖流表层水北伸最强,厚度最厚,温度最低,盐度最高,硅酸盐和硝酸盐偏高,而夏季,则北伸最弱,厚度最薄,温度最高,盐度最低,硅酸盐和硝酸盐偏低;台湾暖流深层水是一个季节性水团,它含有较丰富的营养盐;黄海混合水的分布范围和营养盐含量也都呈现出明显的季节特征.

Seasonal characteristics in the water masses in Zhoushan fishing ground and adjacent region

The Zhoushan fishing ground is located in the shallowwater area of the northwest East China Sea.The formation and displacement of the fishing ground and variations in fishing season and fish crop are mainly affected by hydrologic conditions and nutrient contents there,whose variations,to a great extent,depend on the occupancy range and vanishing-growing changes in water masses.Using the data observed before the year of 1990,the water masses in the northwest East China sea have been studied by some scientists at home and abroad,but the study on the water mass in this sea area after completion in the three gorges engineering has been not reported so far.In this work,based on CTD and nutrient data obtained during the summer of 2001 and the winter of 2002,the water masses in Zhoushan fishing ground and adjacent region were divided by using the fuzzy clustering method,and the seasonal characteristics in distributions,thermohaline properties and nutrient contents in the water masses in this area were analyzed.The results showed that there are distinct seasonal characteristics in the distributions,ranges,thermohaline property and nutrient contents of the water masses in this area.In the whole study area,there are three water masses,namely,Jiang-Zhe Coastal Water(JCW),Taiwan Warm Current Surface Water(TWCSW) and Yellow Sea(Huanghai Sea) Mixing Water(YSMW) in winter,while there are four water masses,namely,the JCW,the TWCSW,Taiwan Warm Current Deep Water(TWCDW) and the YSMW in summer.The JCW has a relative small occupancy range,low temperature,high salinity and high nutrients in winter;while it has a relative large occupancy range,high temperature,low salinity and low nutrients in summer.The TWCSW extends farther northwards in winter than in summer and its thickness is much larger in winter than in summer.In the TWCSW,temperature is low,salinity is high,SiO3-Si and NO3-N are relative high,and PO4-P is low in winter,while the temperature high,salinity low,SiO3-Si and NO3-N relative low,and PO4-P high in summer.The TWCDW is a seasonal water mass,and there are relative rich nutrients in it.There are some seasonal characteristics in the occupancy range and nutrient contents of the YSMW.