近10年中国16个台站大气气溶胶光学厚度的变化特征分析

Characteristics of Atmospheric Aerosol Optical Depth over 16 Radiation Stations in the Last 10 Years

应用宽带消光法从1993～2002年中国16个辐射观测站小时累积太阳直接辐射资料,反演了逐时气溶胶光学厚度值,并统计日、月、年的平均值,用作气溶胶光学厚度变化特征分析。结果表明,16个辐射站总的年平均气溶胶光学厚度在0.32～0.36之间变化,沈阳和郑州两站的气溶胶光学厚度有明显增加的趋势,而哈尔滨、兰州、广州、北京等站气溶胶光学厚度则有明显减弱的趋势。就季节变化而言,一般气溶胶光学厚度最大值出现在春季。月平均气溶胶光学厚度与月平均能见度有较好的负相关关系。

Hourly aerosol optical depths were retrieved by using broadband extinction method from hourly cumulation direct radiation data in 16 stations during 1993—2002, and daily, monthly, yearly aerosol optical depths were calculated repeatly at the same time in order to analyze variation characteristics of aerosol optical depth. It is shown that the yearly averages of aerosol optical depths for all stations varied from 0.32 to 0.36. Increasing trends over Shenyang and Zhengzhou, decreasing trends over Harbin, Lanzhou, Guangdong and Beijng have been found in the period. The maximum aerosol optical depth occurs usually in spring. Monthly average of aerosol optical depth has a good negative correlation with visibility.