1980—2018年南海海表温度时空分布研究浅析

Analysis of the sea surface temperature spatial and temporal distribution in the South China Sea from 1980 to 2018

利用1980—2018年ECMWF中心月平均海表温度(SST)数据以及NOAA物理实验室Ni o 3.4指数,基于EOF分析等方法对南海SST数据进行时空变化分析,研究结果表明:1980—2018近40 a,南海SST距平场存在3个主要的时空分布结构,即以EI Ni o周期信号的海盆尺度和吕宋冷涡的分布、以西北-东南反向分布的夏季热带气旋沉降流、夏季沿岸流与冬季南海暖流分布和以东北-西南反向分布的冬季台湾附近的黑潮以及由黑潮生成的中尺度涡旋、夏季越南沿岸冷涡分布。第一模态主要反映出EI Ni o信号的模态分布,并且在EI Ni o现象发生5个月后,南海海域SST出现全海盆增暖的现象,而第二、三模态主要反映SST季节内变化的模态分布。此外,第二模态与第三模态中,北部湾以北沿岸海域和台湾岛东北海域SST距平场处于正值中心,反映出北部湾海域复杂的流场结构和黑潮水对台湾岛东北部海域的影响。

Using the monthly average sea surface temperature(SST)data of the ECMWF Center from 1980 to 2018 and the Ni o 3.4 index of the NOAA Physics Laboratory,based on EOF analysis and other methods,the spatial and temporal changes of the SST data of the South China Sea sea surface temperature were analyzed.The results show that:in 1980—2018,nearly 40 years there are three main spatiotemporal distribution structures in the SST anomaly field of the South China Sea,namely,the basin scale with Ni o periodic signals and the distribution of the Luzon cold vortex,the summer tropical cyclone subsidence current distributed in the northwest-southeast reverse direction,the coastal current in summer and the warm current in the South China Sea in winter distribution and the distribution of the Kuroshio near Taiwan in the winter from northeast to southwest,the mesoscale vortex generated by the Kuroshio,and the cold vortex in Vietnam in summer.The first mode mainly reflects the modal distribution of the Ni o signal,and 5 months after the Ni o phenomenon occurs,the SST in the South China Sea shows a warming of the entire basin,while the second and third modes mainly reflect the mode of SST seasonal changes state distribution.In addition,in the second and third modes,the SST anomaly field in the sea north of the Beibu Gulf and the northeastern Taiwan island is at the positive center,reflecting the complex flow field structure of the Beibu Gulf sea and the influence of Kuroshio on the waters of northeastern Taiwan Island.