Analysis of the Aerosol Extinction Characteristics in Different Areas of China

The multi-wavelength aerosol optical depths and the Angstrom exponent between 450 nm and 900 nm in four locations of China (Miyun, Beijing; Xinfeng, Guangdong; Waliguan, Qinghai and Damxung, Tibet)have been observed by sun-photometers. This paper analyzes their characteristics for a one-year period from February 1998 to January 1999. The results show that in the arid and semi-arid locations like Miytun (117.12°E, 40.65°N) and Waliguan (100.90°E, 36.29°N), there is a maximum of aerosol optical depth in the spring, it is about twice as large as in any other season. In a humid region like Xinfeng (114.2°E, 24.5°N), theaerosol optical depth also has a maximum in the spring, however it is only slightly larger than in other sea sons. The Angstrom exponent shows a significant minimum at Waliguan in spring, about 0.15, indicating relatively large dust aerosol particles. Large variability of the monthly mean Angstrom exponent is also found in Miyun and Xinfeng, but there is no tendency with seasons. It means that the source of aerosol in these locations is complicated.