舟山以东浅水海域夏季水团及温盐日变化特征

为了探索舟山以东浅水海域夏季水团分布及温、盐日变化规律,基于舟山以东浅水区域时间分辨率为1h的温盐深(CTD)站点数据,首先对数据剖面取平均以研究其温、盐场结构特征,然后利用Fuzzy聚类法对该区域进行水团划分,最后根据水团划分结果分区域统计分析跃层特征,并计算温、盐日变幅极差值以研究其日变化空间的分布特征。结果表明:研究区域可分为沿岸流水团、近岸混合水团、黑潮水团、东海中-深层水团、东海中-深层混合水团;受黑潮支流与沿岸流混合下沉的影响,调查海域中部中-深层水体相对高温、低盐;沿岸流区与黑潮水区10~20m深度层的温、盐日变幅较大,与跃层深度对应较好,表层、次表层的较小,底层的近似为0;近岸混合水团跃层上界深度最大、平均强度最小,该区域表层、底层日变幅相对较大。

Water mass and temperature/salinity daily variation in east shallow-water area of Zhoushan

In order to analyze the water mass distribution and temperature/salinity daily variation characteristics,the investigation conductance temperature depth(CTD) data in the east shallow-water area of ZhouShan with 1 hour of temporal resolution were used in this paper. Firstly, the data were averaged to study their characteristics of temperature/salinity structure. Then, the water mass was classified of the investigation area with Fuzzy cluster method. Lastly, according to the cluster result, a statistic analysis of thermocline was made respectively, and the temperature/salinity daily variation amplitude extreme difference calculated to research the spacial distribution characteristics of the daily variation. The major results are as follows:(1) The research area can be classified into coastwise low salinity water mass, alongshore mixture water mass, Kuroshio water mass, and East China Sea middle-deep water mass, East China Sea middle-deep mixture water mass. (2) With the influence of mixture and sinkage of Kuroshio branch and coastwise current, the water of middle and deep layer takes on the characteristics of relative low salinity and high temperature. (3) In the area of coastwise and Kuroshio, the temperature/salinity daily variation is big between the layer of 10~20 m which corresponds to the thermocline depth, while whose surface and subsurface layer is small and the bottom layer is almost equal to zero. (4) In the area of alongshore mixture water, the upper depth of thermocline is the biggest, while the average intensity of thermocline is lowest, and the daily variation of the surface and bottom layer is bigger.