92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Thursday, 26 January 2012: 9:30 AM
Absorption Spectral Variation to Illustrate Regional and Seasonal Asian Aerosol Variation
Room 342 (New Orleans Convention Center )
Timothy Logan, University of North Dakota, Grand Forks, ND; and B. Xi, X. Dong, Z. Li, M. Cribb, and W. Gong

Poster PDF (4.3 MB)

The ongoing urbanization and industrialization in Asia have contributed to more different types of aerosols in the atmosphere, consequently adding more uncertainty to the global climate. To investigate the different kind of aerosols and their optical properties, we have selected four AERONET sites and one research facility which represent four different aerosol regimes: Clean air (Nam Co site, 30.8oN, 90.9oE, southeast of the Tibetan Plateau), mineral dust (Dalanzadgad, Mongolia, 43.6oN, 104.4oE), pollution (Taihu site, 31.4oN, 120.2oE and Wuhan, 30.5oN, 114.3oE), and a mixture of pollution and mineral dust (Xianghe site, 39.7oN, 116.7oE). The seasonal variations of extinction (AOD, AE, and DA) and absorptive (AAOD, AAE, and ADA) aerosol properties over the five selected sites have been explored using a range of datasets from 1997 to 2010. Three main types of aerosols have been found in this study, they are mineral dust (naturally derived), pollution (anthropogenic), and biomass (both natural and anthropogenic). Mineral dust is dominant over all five sites during the spring months with a strong absorbing in nature. Conversely, during the summer months, there is a changeover from absorbing aerosols to scattering aerosols which are of a finer mode. In the winter months, the much higher AAOD and AAE values over Xianghe and Taihu indicate more absorbing aerosols or pollution caused by coal burning for residential heating. The absorption spectral variation technique (ADA) has been used to discern the contribution of different types of aerosols to the overall AOD, suggesting a relative larger seasonal variation of aerosol properties at Xianghe as compared to Taihu and Dalanzadgad because Xianghe is influenced by both mineral dust and pollution. Moreover, the ADA parameter over Xianghe shows the largest range of values (0.1-0.71) with an annual mean of 0.51. The other three sites do not reflect this variation but do show influences of either mineral dust and biomass aerosols. For example, Taihu has an annual mean ADA of 0.48 but exceeds the annual mean in winter and spring due to coal burning and mineral dust, respectively. Dalanzadgad has summer ADA values of 0.12 which is much less than the annual mean of 0.24 due to biomass aerosol intrusions.

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