Huang Zhida, Zhuang Wei, Liu Hailong, Hu Jianyu
State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China.
Key Laboratory of Coastal and Wetland Ecosystems of Ministry of Education, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China.
Sci Rep. 2018 Feb 15;8(1):3074. doi: 10.1038/s41598-018-21364-3.
Based on three climatologically observed temperature and salinity datasets (i.e., GDEM-V3, SCSPOD14 and WOA13), this paper reports a low-salinity (~34.32) water mass in the subsurface-to-intermediate layer around the Xisha Islands in the South China Sea. This water mass mainly subducts from the surface layer into the intermediate layer, characterized by a relatively low potential vorticity tongue extending from the bottom of mixed layer to the thermocline, and accompanied by a thermocline ventilation in spring (especially in April). The potential dynamics are the joint effects of negative wind stress curl, and an anticyclonic eddy triggered by the inherent topographic effect of the Xisha Islands, reflecting that downward vertical motion dominates the subduction. Despite lacking of the homogenous temperature and density, the low-salinity water mass is to some extent similar to the classic mode water and can be regarded as a deformed mode water in the South China Sea.
基于三个气候学观测的温度和盐度数据集（即GDEM-V3、SCSPOD14和WOA13），本文报道了南海西沙群岛周围次表层至中间层存在一个低盐度（约34.32）水体。该水体主要从表层俯冲至中间层，其特征是有一个从混合层底部延伸至温跃层的相对低势涡舌，并在春季（特别是4月）伴有温跃层通风现象。潜在动力学是负风应力旋度以及由西沙群岛固有地形效应触发的反气旋涡共同作用的结果，反映出向下的垂直运动主导了俯冲过程。尽管缺乏均匀的温度和密度，但该低盐度水体在一定程度上与经典模态水相似，可被视为南海的一种变形模态水。
