印度夏季风的减弱及其与对流层温度的关系

对43aNCEP/NCAR再分析资料和台站实际观测资料的分析,揭示了对流层温度变化和印度夏季风环流减弱之间的联系。印度夏季风的变化与东亚上空对流层温度具有密切的关系,主要表现为对流层平均温度与整个印度夏季降雨和季风环流强度之间存在显著的正相关。结果表明:印度夏季风环流在近几十年经历了两次减弱过程,第一次减弱约发生在20世纪60年代中期,第二次减弱则发生在20世纪70年代后期;通过改变海陆热力对比,对流层平均温度在印度夏季风减弱过程中可能起着重要作用,东亚地区与东印度洋至西太平洋热带地区之间的对流层温度差异导致了印度夏季风环流的减弱。

WEAKENING OF INDIAN SUMMER MONSOON AND ITS RELATION WITH TROPOSPHERIC TEMPERATURE VARIATION

The analysis of 43-year NCEP-NCAR reanalysis data and the station observations reveals the correlation between troposphere temperature variations and the weakening of the Indian summer monsoon circulation. The Indian summer monsoon variation is strongly linked to tropospheric temperature over East Asia, showing significant positive correlations of mean tropospheric temperature with all-Indian summer rainfall and the monsoon circulation intensity. The result shows Indian summer monsoon circulation underwent twice-weakening processes for recent decades. The first occurred in the circ. mid-1960s, and the other occurred in the circ. late 1970s. The finding indicates that the mean tropospheric temperature may play a crucial role in weakening of the Indian summer monsoon intensity via changing land-sea thermal contrast. The troposphere temperature contrast between East Asia and the tropical area from the eastern Indian Ocean to the tropical western Pacific lead to weaken the Indian summer monsoon circulation.