基于CE318观测的广州市气溶胶光学特性

基于CE318太阳分光光度计观测数据，反演了广州市2011年全年的气溶胶光学厚度、浑浊度和波长指数，并对广州市气溶胶光学特性的全年总体特征、季节性特征、日变化等进行了分析。结果表明：1）2011年广州市气溶胶光学厚度（AOD）全年均值为0.53，处于较高水平。其中，春季AOD最大，均值为0.81秋冬季其次，均值为0.5左右；夏季最小，均值为0.43。浑浊度与光学厚度具有相似的特点。2）从频率分布上看，波长指数α＞1.2所占比例接近90%，在1.4~1.6之间的所占比例＞50%，说明广州市的气溶胶主控粒子为小粒径的烟雾粒子。3）广州市秋冬季节的波长指数α较大，分别为1.46和1.50；春季α为1.27，夏季α为1.13。春夏季节粗粒子有较大程度地增多。总体上看，广州市区气溶胶类型接近于城市-工业性气溶胶与海洋性气溶胶的混合类型。4）广州市AOD的日变化与人类活动较为一致，上午持续上升，中午T 13:00左右到达一个小高峰，随后趋于稳定，T 17:00左右开始缓慢上升。波长指数α与AOD无明显关系。

Aerosol Optical Properties in Guangzhou Based on the CE318 Data

A CE318 automatic sun tracking spectrophotometer was used to measure direct solar radiation at Guangzhou in 2011. The Aerosol Optical Depth (AOD), wavelength exponent (α), turbidity (β) were retrieved, of which the annual and seasonal characteristics and the diurnal variation were studied. The results show that: 1) The average value of AOD at Guangzhou in 2011 was 0.53, which was at a relatively high level. The AOD varied seasonally, with a spring maximum (0.81), autumn and winter next (0.5)and a summer minimum (0.43). The turbidity had the same feature with the AOD. 2) The proportion of the wavelength exponent above 1.2 was nearly 90% in terms of frequency distribution, while that between 1.4~1.6 was more than 50%. That showed that the fine particles were the principle aerosol particles. 3) The wavelength exponents in autumn and winter were both larger, the values of which were 1.46 and 1.50 respectively. The value of wavelength exponent in spring was 1.27, while that in summer was 1.13. The coarse particles increased in spring and summer. Overall, the aerosols in Guangzhou were the mixture of the industry-urban aerosol and the maritime aerosol. 4) The diurnal variation of AOD at Guangzhou was consistent with that of human activities, AOD was continuously rising in the morning, and reached a peak at 13 o’clock, then tended to be stable, and it rose slowly from 17 o’clock on. The wavelength exponent had no obvious relationship with AOD.