根据2011年8月19日至9月12日南海北部开放航次的温、盐资料, 采用模糊聚类分析方法, 结合8、9月份的卫星高度计资料, 研究了2011年夏季南海北部海区水团的特征和分布状况。在垂直方向上将南海北部水团划分为5类: 近岸混合水团、南海表层水团、南海次表层水团、南海中层水团和南海深层水团, 并对南海各个水团的分布, 温、盐特性进行了细致的分析。结果显示, 2011年夏季有黑潮水入侵南海, 入侵范围止于119°E。结合卫星高度计资料反演的地转流场发现, 流场内部有多个中尺度涡, 主要包括东沙群岛东侧和吕宋海峡东侧的反气旋涡, 以及东沙群岛南端的气旋涡, 说明2011年夏季南海北部环流具有显著的多涡结构, 并且该多涡结构对水团的垂向分布及黑潮入侵范围产生了一定影响。

Using the hydrographic data collected during August 19 to September 12, 2011 and the altimetry data, we studied the characteristics and distribution of water masses in the northern South China Sea (SCS). In this study, fuzzy cluster analysis of temperature and salinity data was employed to categorize the water in the northern SCS vertically in terms of five groups: the coastal mixing water mass (M), the surface water mass (S), the subsurface water mass (U), the intermediate water mass (I), and the deep water mass (D). Results show that there is Kuroshio water intrusion into the SCS in summer 2011, and that the intrusion could reach 119°E. The geostrophic currents derived from the altimetry data show several meso-scale eddies, including two anticyclonic eddies east of Dongsha Island and east of the Luzon Strait, respectively, and a cyclonic eddy south of Dongsha Island. This indicates distinct meso-scale structures of the circulation in the northern SCS in summer 2011, which would influence the vertical distribution of water mass and the Kuroshio intrusion.