该文发展了遥感气溶胶光学厚度的一个宽带消光遥感方法,它应用地面上太阳直射表探测的宽波段太阳直射信息反演0.75μm大气柱光学厚度。这方法的主要误差因子是气溶胶谱的不确定性。数值试验表明,气溶胶谱分布的误差所引起光学厚度解的误差一般小于5%。1995年1-10月进行的1267组对比实验表明,由本方法探测的气溶胶光学厚度与光度计探测的气溶胶光学厚度的标准差为10.5%,两者平均结果的偏差只有0.7%。

Based on sensitivity of the direct solar short radiation on the aerosol property,a so called wide band extinction method is proposed to determine the 0.75μm aerosol opitical depth using th eradiation,and its accuracy is analyzed according to numerical simulations and comparative measurements As shown in numerical simulations using Junge and LOWTRAN aerosol size distributions,the depth solution error of <5% can generally be expected if a typical Junge distribution of v^*=3 is taken instead of true distribution The method is tested in comparative observations with the result that aerosol optical depths measured by pyrheliometer conform well with those by sunphotometer As far as total 1267 sets of comparative experiments are concerned,the standard deviation is 10.5%,and the deviation of the mean optical depth only-0.7% Monthly mean or yearly mean result would have much better accuracy The present method is used in determining 0.75μm aerosol optical depths from the direct solat radiation detected by the phyrheliometer over 10 sites in China during 1980-1994 The 10 sites are meteorological observatories of Beijing,Shenyang,Wulumuqi,Germo,Keshi,Zhengzhou,Wuhan,Shanghai,Kungming and Guangzhou Some conclusions are: (1) Except Shenyang,aerosol optical depths over other 9 sites have an increasing trends with the annual increasing rates changing from 0.0008(Germo)to 0118(Beijing) (2) Pinatubo vocalnic eruption in 1991 had very great influence on aerosol optical depth Compared to that before 1990,the aerosol optical depths in 1992 over the ten sites increased obviously from 0.041 to 0.295 (3) In Wuhan,Beijing,Shenyang,Guangzhou and Zhenzhou cities,aerosol pollution was rather seriousq The total means of the aerosol optical depths during 1980-1994 were all more than 0.4,and especially in Wuhan,0.551 Germo and Kunming were relatively clear,and in particular in Germo it was only0 1687 (4) In the five sites of Kunming etc in the southern of Yellow River,the aerosol optical depths were relatively big in spring Except Wulumuqi,in the sites in the northern of Yellow River,they were relatively high in spring and summer and low in autumn and,inWulumuqi and Shenyang,they were comparatively high in winter.