中文摘要：

基于2004-2012年8-9月份南海北部开放航次期间18°N断面的温盐深仪（Conductance Temperature Depth,CTD）观测资料,分析了夏末秋初沿18°N断面的温度、盐度和混合层结构特征及其影响因素。研究发现：南海18°N断面的温度、盐度和混合层特征具有显著的年际变化,并且混合层的深度和其倾斜程度与风速及风驱动的Ekman平流有关,而所有航次18°N断面东侧均出现等温线、等盐线下凹现象,这与夏末秋初吕宋岛西侧海域存在一个反气旋式涡旋活动有关。

英文摘要：

Based on the Conductance Temperature Depth（CTD） data observed during the Northern South China Sea Open Cruise（NSCSOC） in late August or early September from 2004 to 2012, the characteristics of the temperature, salinity and Mixed Layer Depth（MLD） are studied through the cross section 18° N in the South China Sea. The result shows that the temperature, salinity and the MLD present interannual variability along the section 18° N in the South China Sea, and the MLD and its slope are related to the wind speed and the advection resulted from Ekman current. All the contour lines of the temperature and salinity cross the section 18° N during 2004 to 2012 are concave, which is associated with the anticyclonic eddy existing in the west of the Luzon Strait.