热带地区100 hPa东风气流的气候效应(Ⅰ): 与华南气候的关系

利用NCEP／NCAR再分析资料、西太平洋副热带高压(下称西太副高)指数距平资料,分析了热带地区100hPa东风强度与华南气候之间的关系。结果表明：(1)冬季东风强度与同期及3月份华南降水存在显著的负相关关系。合成分析表明,弱东风年冬季华南地区700hPa为西南风距平,有利于孟加拉湾的暖湿空气向华南上空输送。(2)前期秋冬季节平均东风强度与区域平均的华南夏季气温之间存在很好的相关关系,相关系数达到-0．617。合成分析发现,弱东风年夏季西太副高偏强,位置偏西,使得华南地区在强副高控制之下,多为晴空少云天气,气温偏高。

Climatic Effects of 100 hPa Easterly Air Flow in Tropical(I): Its Relationship with Climate Anomalies in South China

The relation between the tropical easterly intensity at 100 hPa and climate anomaly in South China is analyzed by using the data of NCEP/NCAR reanalysis and the index of the west Pacific subtropical high. The results are as follows:(1) There is a remarkable negative correlation between the winter easterly intensity and both the same time and the March rainfall in South China. The composite analysis shows that there is a southwesterly anomaly over the IndochinaPeninsular and South China in week easterly year, which is favourable to transfer the warm and moist water vapor from the Bay of Bengalto the South China. (2) The summer air temperature averaged over South China has a close relationshipwith the previous easterly intensity average from the October in the last year to the February in the same year, and their correlation coefficients are -0.617. The composite analysis shows that the west Pacific subtropical high is stronger than ever, and its western limit is far westward in the weak easterly year. As a result, the clear days are more than ever in the South China and the air temperature is higher.