摘要
Aerosol optical properties from August 2006 to July 2007 were obtained from ground-based and sky radiance measurements in Semi- Arid Climate and Environment Observatory of Lanzhou University （SACOL）, China. High aerosol optical thickness （AOT） associated with low .Angstrom exponent （α） was mainly observed in spring, which was consistent with the seasonal dust production from Hexi Corridor. The maximum monthly average value of AOT 0.56 occurred in March of 2007, which was two times larger than the minimum value of 0.28 in October of 2006. Approximately 60% of the AOT ranged between 0.3 and 0.5, and nearly 93% ofα value varied from 0.1 to 0.8, which occurred in spring. The significant correlation between aerosol properties and water vapor content was not observed. The aerosol volume size distribution can be characterized by the bimodal logarithm normal structure： fine mode （r 〈 0.6 μm） and coarse mode （r 〉 0.6 μm）. Aerosols in spring of SACOL were dominated by large particles with the volume concentration ratio of coarse to fine modes being 7.85. The average values of asymmetry factor （g） in the wavelength range 440-1020 nm were found to be 0.71, 0.67, 0.67 and 0.69 in spring, summer, autumn and winter, respectively.
Aerosol optical properties from August 2006 to July 2007 were obtained from ground-based and sky radiance measurements in Semi- Arid Climate and Environment Observatory of Lanzhou University （SACOL）, China. High aerosol optical thickness （AOT） associated with low .Angstrom exponent （α） was mainly observed in spring, which was consistent with the seasonal dust production from Hexi Corridor. The maximum monthly average value of AOT 0.56 occurred in March of 2007, which was two times larger than the minimum value of 0.28 in October of 2006. Approximately 60% of the AOT ranged between 0.3 and 0.5, and nearly 93% ofα value varied from 0.1 to 0.8, which occurred in spring. The significant correlation between aerosol properties and water vapor content was not observed. The aerosol volume size distribution can be characterized by the bimodal logarithm normal structure： fine mode （r 〈 0.6 μm） and coarse mode （r 〉 0.6 μm）. Aerosols in spring of SACOL were dominated by large particles with the volume concentration ratio of coarse to fine modes being 7.85. The average values of asymmetry factor （g） in the wavelength range 440-1020 nm were found to be 0.71, 0.67, 0.67 and 0.69 in spring, summer, autumn and winter, respectively.
基金
supported by the National Basic Research Program (973) of China (No. 2006CB403706)
the National Natural Science Foundation of China (No.40875078)
the Key Basic Research Program of Natural Science for University of Jiangsu (No. 08KJA170002)
the Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing University of Information Scienceand Technology (No. KLME20060302, KLME060209,KLME0907)
the Shanghai Tongji Gao Tingyao Environmental Science & Technology Development Foundation
