Abstract: Dust aerosol,naturally generated and affected by the underlying surface and weather,is one of the main components of tropospheric aerosols.It also leads to severe dust retention in a storm.In northwest China,spring (from March to May) is the dust storm season.Sandstorms and local sandstorms lift large quantities of dust into the air and bring them to downstream area.This would cause a continuous high concentration of dust aerosols in northwest China.The frequent occurrence of sandstorm severely affects the normal life of the residents and causes great losses to property of residence and society as a whole.Moreover,dust carried by sandstorms also has impact on the radiation balance of the earth's atmosphere system through direct or semi-direct radiation,and then affects the regional and global climate.In order to analyze the influence of sand and dust on total solar radiation and atmospheric inverse radiation,the data of the surface radiation and solar photometer were obtained by both Lanzhou University and Maryland University at Zhangye station from April 18 to June 15 in 2008.The surface radiation and solar photometric data at cloudless and sunny noon was chosen to eliminate the influence of cloud on atmospheric transmittance.The atmospheric turbidity is obtained by optical thickness interpolation of different wavebands.The atmospheric transmittance is calculated by the function of atmospheric turbidity and atmospheric transmittance.Then,the value of total solar radiation is calculated.After comparison,the calculated value is basically in line with the observed value,and the error is below 1%.The results showed that dust in the air can reduce the solar radiation reached to the surface,the estimation of reduction is 10.45 W·m^-2 while 0.1 atmospheric turbidity is added.If the atmospheric turbidity is constant,the smaller the dust particles are,the higher the efficiency of reduction of dust will be.By analyzing the trend of the inversion of the gas and the atmospheric turbidity,it indicated that when atmospheric turbidity value is less than 0.3,there is a trend that atmospheric inverse radiation increases with the atmospheric turbidity; when atmospheric turbidity value is greater than 0.3,the atmospheric inverse radiation decreases with the atmospheric turbidity.In the process of atmospheric turbidity,the decrease of temperature is a main factor.The decrease amount of atmospheric inverse radiation caused by temperature is greater than that by dust.Therefore,there is an inverse relationship between atmospheric inverse radiation and atmospheric turbidity.

Key words: dust aerosols, radiation, atmospheric transmittance, optical thickness