基于SODA数据集的南海海表面盐度分布特征与长期变化趋势分析

盐度是南海物理环境的重要组成部分之一,盐度的变化对南海的水动力环境有重要影响。利用1972-2010年的SODA数据集的5.01 m层月平均数据,分析南海海域海表面盐度的时空分布特征,采用基于最小二乘法的线性拟合分析南海海表面盐度的长期变化趋势。结果表明南海海域的海表面盐度在39 a间90%以上区域均呈现盐度下降趋势,整个海域SSS则以每年0.005 88 psu的速率下降,春季SSS下降速率最大为0.006 4 psu/a,夏季SSS下降速率在四季中最小为0.005 19 psu/a。

Analysis on the Distribution Characteristics of Sea Surface Salinity and Its Long-Term Variation Trend in the South China Sea Based on SODA Data Set

Salinity is one of the important parameters of the physical marine environment and its variation has significant effects on the hydrodynamic environment in the South China Sea. The monthly average data of 5.01 m layer from the SODA data set from 1972 to 2010 are used to analyze the space-time distribution features of sea surface salinity and the linear fitting based on the least square method is adopted to obtain the long-term trend of sea surface salinity in the South China Sea. The results show that during 39 years, more than 90% coverage of the South China Sea saw a declining trend of the sea surface salinity which declines at a rate of about 0.00588 psu per year on the entire ocean area, with the maximum of 0.0064 psu/a in the spring and the minimum of 0.00519 psu/a in the summer.