中文摘要：

利用DTF型太阳光度计在我国几个典型城市地区较长期观测得到的资料，分析了不同地区气溶胶光学厚度日变化和季节变化特征，得到了各地区观测期间El均值、月均值和季节值的变化。结果显示，观测期间丽江地区气溶胶光学厚度最小，大气较洁净，大气中以细粒子为主；其次是张北；喀什和合肥地区气溶胶光学厚度都较大，但喀什、张北多以粗粒子为主，合肥多以细粒子为主。各地区都在春季气溶胶光学厚度较大，冬季最小。喀什的气溶胶光学厚度值多集中在0．15到0．7之间，张北多集中在0．08到0．4之间，合肥多集中在0．2到0．75之间，丽江多集中在0．01到0．1之间。各地区气溶胶光学厚度和Angstr6m波长指数频率分布基本呈高斯分布，气溶胶光学厚度峰值分布由高到低依次为合肥、喀什、张北、丽江，Angstr／Sm波长指数由高到低依次为丽江、合肥、张北、喀什。

英文摘要：

The diurnal variation characteristics of Aerosol Optical Thickness（AOT） in different city re gions and seasons were analyzed by using the longterm measurement data from a sunphotometer DTF in several typical regions of China. It indicates that the AOTs in Chinese different regions show complex and different diurnal variation characteristics and the diurnal variation trend is obviously dif ferent. The AOT variations of yearlymean, monthlymean, and seasonalmean in each region were al so presented. The results show that the AOT in Lijiang of Yunnan Province is the least, where the at mosphere is clean, and the small particles are dominant, and that in Zhangbei of Hebei Province is the second least one. The AOTs both in Kashi of Xinjiang province and Hefei of Anhui province are lar ger, and the bigger particles are dominant in Kashi while the smaller particles are dominant in HefeiIn every region, the AOT is larger in spring, and the smallest in autumn. Moreover, the value of AOT is between 0. 15 and 0.7 in Kashi, 0.08 and 0.4 in Zhangbei, 0.2 and 0.75 in Hefei, 0.01 and o 0.1 in Lijiang, respectively. The frequency distributions of AOT and Angstrom index are basically Gauss distribution. The peak value distribution of AOT from high to low is Hefei, Kashi, Zhangbei, and Lijiang in turn and that of the Angstr6m index from high to low is Lijiang, Hefei, Zhangbei, and Kashi in turn.