南海夏季风爆发前后SST异常特征及其与近地面西南气流的关系

Anomalous Characteristics of SST Variation in South China Sea before and after Onset of Summer Monsoon and Relation with Surface Southwest Air Current

利用1982-1999年周平均海表温度资料和逐日近地面风场资料,采用合成分析与相关分析技术,研究了南海和孟加拉湾地区夏季风爆发前后短时间尺度SST变率的异常及其与近地面西南气流的关系。结果表明：季风爆发前2周,南海和孟加拉湾海温的上升除与海洋现象有关外,还与大气的影响因子有一定的关系;季风爆发后1-2周,南海和孟加拉湾海温变率出现较大差异,二者西南部海温降低,而其东海岸及西北部海温却升高;海温变率这种异常分布与西南气流的变化具有较好的相关性,即西南气流的增强导致南海西南部和孟加拉湾西南部海温降低及二者东海岸与西北部海温升高,这是由于离岸的上翻作用及海洋蒸发作用共同所致。

The SST variation characteristics over the South China Sea （SCS） and the Bay of Bengal before and after the onset of summer monsoon and the possible relation with Southwest air current are investigated by means of the NCEP/NCAR weekly-mean SST reanalysis data and daily-mean surface wind data from 1982 to 1999, using synthetic and correlation analysis technique. The results show that the SST increase on SCS and the Bay of Bengal is not only related to ocean phenomena, but also to atmospheric factors in the two weeks before the monsoon onset. There were great difference in the regional SST variability between SCS and Bay of Bengal in the two weeks after monsoon onset. The SST increased in the east coast and the northwest part of the and the Bay of Bengal, and decreased in the southwest and central parts of the SCS and the Bay of Bengal. The disparity distributions of SST variation are directly related with the surface southwest current variation in the two weeks after monsoon onset.