THE COOLING OF SICHUAN PROVINCE IN RECENT 40 YEARS AND ITS PROBABLE MECHANISMS

The analysis of temperature variation trends at 160 meteorological stations in China from 1951 to 1992 showed that a relatively large area of China became warm in recent years,but there still existed an obvious cooling center in Sichuan basin.We also analyzed the variation trends of some meteorological factors which could probably cause this cooling,and the results indicated that the global solar radiation,the insolation duration and the visual range decreased sharply in recent years,but the cloud amount changed slightly in Sichuan basin.We also found that the decrease of surface solar radiation caused by the increase of the anthropogenic aerosols' backscattering in the lower troposphere was a notable reason for the cooling of Sichuan basin in recent years.We also confirmed this conclusion by using of a one-dimensional climate model.