东海PN断面障碍层和水团的季节变化特征及其可能联系  

Seasonal variation of the water mass and the barrier layer along the PN section in the East China Sea and their possible relationship

作　　者：张媛[1,2] 吴德星[2] 林霄沛[2] 

机构地区：[1]南京信息工程大学大气科学学院,南京210044 [2]中国海洋大学物理海洋实验室,青岛266003

出　　处：《南京大学学报（自然科学版）》2009年第6期734-745,共12页Journal of Nanjing University（Natural Science）

基　　金：国家基础研究规划(2005CB422303;2007CB411804);国家科技合作(2006DFB21250);国家自然科学基金(40706006;40906005);高校引智计划(B07036)

摘　　要：本文利用PN断面的高分辨率海水温-盐-深剖面测量仪(CTD)温度、盐度和密度资料进行分析,发现PN断面处的水团有明显的陆架水和黑潮水的交汇特征,且随着季节的变化PN断面处的水团特征也发生明显的变化.通过观测资料还确定了PN断面处障碍层是常年存在的而且具有显著的季节变化.采用曲线族拟合的水团分析方法,根据不同季节PN断面上陆架水和黑潮水的混合特征,证明了水团混合在障碍层形成及季节变化中的重要作用,发现障碍层的季节变化与陆架水团和黑潮水团混合的季节变化密切相关.夏季,陆架水团向外海延伸,浮置于黑潮水之上,此时障碍层深度最浅,障碍层厚度最大;秋季,黑潮水离岸最近,将黑潮水与陆架水的交汇处向西压迫至陆架内,此时几乎不存在障碍层,零星存在的障碍层深度较深,厚度是一年当中最薄的;冬季,由于黑潮水的核心相对于秋季向深海移动,使得陆架混合水也相应地向外海拓展,而且此时陆架水与黑潮水的交汇处不只在混合层内而是影响到跃层,此季节障碍层是一年当中深度最深,厚度最厚的;春季,黑潮水的核心以及两种水团的交汇处相对于冬季的位置更向深海移动,所以此时PN断面上的障碍层深度和厚度相对于冬季变化不大,只是位置东移.海面风场和净热通量场通过改变混合层的深度影响障碍层深度的季节变化,而海面降水对于季节平均的障碍层分布和变化都没有显著的影响.Based on the hydrographic conductivity-temperature depth sensors（CTD） data and the vertical gradient method, we have examined the seasonal variation of barrier layer along the PN transect in the East China Sea. The seasonal variation of the barrier layer is determined by the water mass mixed in the continental shelf. In summer, the continental shelf water stretches towards the deep sea and floats over Kuroshio. The depth of the barrier layer in this season is the shallowest. In autumn, Kuroshio is the dosest to nearest the continental shelf. The encountering area of them is suppressed to the continental shelf. There is almost no barrier layer and the sporadic barrier layer is thin and its depth is deep. In winter, both Kuroshio and the continental shelf water move towards the deep sea, and the encountering position is deep enough to influence the pycnocline in the deep sea. So the barrier layer in winter is the deepest and thickest of the year. In spring, the encountering position of the two water mass moves towards the deep sea relative to winter. Thedepth and the thickness of the barrier layer in spring are similar to those in winter, while its position moves eastward. The sea surface wind stress and net heat flux in the PN section affect the seasonal variation of the barrier layer depth by changing the mixed layer depth every season. However, there is no obvious influence from precipitation to the seasonal variation of barrier layer distribution.

关 键 词：PN断面 障碍层 水团 降雨 风场 净热通量 季节变化 

分 类 号：TV213[水利工程—水文学及水资源] P343.5[天文地球—水文科学]