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Pan, LA, Che, HZ, Geng, FH, Xia, XG, Wang, YQ, Zhu, CZ, Chen, M, Gao, W, Guo, JP (2010). Aerosol optical properties based on ground measurements over the Chinese Yangtze Delta Region. ATMOSPHERIC ENVIRONMENT, 44(21-22), 2587-2596.

The characteristics of Aerosol Optical Depth (ADD) and Angstrom exponent were analyzed and compared using Cimel sunphotometer data from 2007 to 2008 at five sites located in the Yangtze River Delta region of China. The simultaneous measurements between Lin'an and ZFU showed a very high consistency of AOD at all wavelengths. The differences are less than 0.02 for Angstrom exponent and ADD at all wavelengths. The mean values of AOD at 440 nm at the Pudong, Taihu and Lin'an were about 0.74 +/- 0.43, 0.85 +/- 0.46, and 0.89 +/- 0.46, respectively. The mean values of Angstrom exponents were about 1.27 +/- 0.30, 1.20 +/- 0.28 and 1.32 +/- 0.35, respectively. The variation of monthly averaged ADD over Pudong showed a single peak distribution, with the maximum value occurring in July (AOD(440nm) 1.26 +/- 0.61) and minimum in January (AOD(440nm) 0.50 +/- 0.27). However, the variations of monthly averaged ADD at Taihu and Lin'an showed a hi-modal distribution. There were peak values of AOD occurring in July (AOD(440nm) 1.41 +/- 0.49) and September (AOD(440nm) 1.22 +/- 0.52) for Taihu. For Lin'an, the two peak values of ADD occurred in June (AOD(440nm) 1.17 +/- 0.69) and September (AOD(440nm) 1.28 +/- 0.46). The ADD accumulated mainly between 0.30-0.90(68%), 0.30-1.20(75%) and 0.30-1.20 (similar to 75%) at Pudong, Taihu, and Lin'an, respectively. The Angstrom exponent accumulated mainly between 1.10-1.60 (75%), 1.10-1.50 (63%) and 1.20-1.60, 50% (50%) at Pudong. Taihu, and Lin'an, respectively. The synchronized observation showed that the ADD at Pudong was larger than those at Dongtan by 0.03, 0.03, 0.04, 0.07, and 0.08 at wavelengths of 1020 nm, 870 nm, 670 nm, 500 nm and 440 rim, respectively. The synchronized observations at Pudong. Taihu and Lin'an showed that the three stations had high level ADD with means at 440 nm about 0.68, 0.73, and 0.78, respectively. The relationship between MODIS retrieved and ground-based measured ADD shows good agreement with R-2 ranging from 0.68 to 0.79 at Pudong, Taihu, Lin'an and Dongtan. The MODIS results were overestimated comparing the ground measurements at Pudong, Taihu, and Dongtan but exceptional at Lin'an. The analysis results between aerosol optical properties and wind measurement at Pudong showed that the wind speed from the east correlates with the lower observed ADD. The back trajectory analysis indicates that more than 50% airmasses were from the marine area at Pudong, while back trajectories distribution is relatively homogeneous at Lin'an. (C) 2010 Elsevier Ltd. All rights reserved.



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