兰州1960—2003年大气气溶胶光学厚度和太阳辐射变化特征

 利用兰州站1960—2003年的太阳辐射资料以及据此反演的气溶胶光学厚度数据,分析了近44 a来兰州气溶胶光学厚度（AOD）、地面能见度和太阳辐射的变化特征。结果表明,20世纪70年代初气溶胶光学厚度增加很快;70年代中期至80年代中期,光学厚度处于较高水平,平均为0.568;90年代以来,光学厚度有波动下降趋势,年下降0.006,且季节间差异有减小趋势。能见度夏季最好,冬季最差;80、90年代能见度有明显变好趋势,年增长为0.340 km;2000年以来又有下降趋势。总辐射和直接辐射的变化可以分为两个时期,1992年之前为下降期,1992年以来有显著上升趋势。

Variation Characteristics of Atmospheric Aerosol Optical Depth and Solar Radiation in Lanzhou during 1960-2003

Using the data of routine solar radiation measurements in Lanzhou during 1960—2003 and the hereby retrieved atmospheric aerosol optical depth (AOD) data, the variation characteristics of AOD, surface visibility and solar radiation were analyzed. The results show that AOD increased in the 44 years, while visibility and solar radiation decreased as a whole. AOD increased quickly in the early 1970s, and then kept on a high level in the next decade with the mean value of 0.568. Entering 1990s, a fluctuant downtrend of AOD was found with the annual decrease of 0.006, and the differences between seasonal AODs were reduced. As to surface visibility, spring had the finest visibility, while winter the worst. During the 1980s and 1990s, visibility showed an uptrend with the annual increment of 0.340 km, but declined again from 2000. The change of global and direct solar radiations fell into two periods in the 44 years, with the decreasing trend in the period of 1960—1991 and the increasing in the period of 1992—2003.