基于MODIS和AERONET的气溶胶地表直接辐射效应评价

气候变化背景下进一步开展高污染地区气溶胶直接辐射效应的研究，对于该地区的大气环境监测、气候变化评估以及农业生产布局等具有重要意义。利用全球气溶胶监测网（AERONET）多年观测资料以及MODIS地表反照率数据，借助6S（Second Simulation of a Satellite Signal in the Solar Spectrum）辐射传输模式，定量评估2001年1月−2016年12月中国AERONET北京、香河和太湖3个典型高污染站点多年晴空条件下的气溶胶直接辐射效应。结果表明：（1）各个高污染站点气溶胶PM2.5质量浓度季节变化特征差异明显，秋冬污染较为严重，其中高值主要集中在1月、2月、11月和12月；（2）与无气溶胶影响相比，气溶胶致使各站点地表直接辐射年际变化较明显。在气溶胶影响下，北京、香河和太湖3个站点2001−2016年地表日平均直接辐射年际变化较明显，均呈波动增加趋势，且香河站日平均直接辐射增加最大（621.14W·m⁻²），太湖站次之（743.29W·m⁻²），北京站最小（488.14W·m⁻²）。（3）气溶胶影响下各站点地表直接辐射明显降低，且气溶胶对各站点影响差异较大。2001−2016年，北京、太湖和香河站年平均地表直接辐射分别降低32.29%、24.01%和15.07%。其中，气溶胶对北京站的地表直接辐射影响最大，香河站最小。（4）近15a来，北京、香河和太湖3个站点气溶胶地表辐射效应均呈现增加趋势。

Estimating Surface Direct Radiation Effect of Aerosol Based on MODIS and AERONET Data

Under climate change, the research on the direct radiation effect of aerosol in high polluted areas is of great significance for atmospheric environment monitoring, climate change assessment and agricultural production distribution in these areas. In this paper, the direct radiation effects of aerosol from January 2001 to December 2016 were quantitatively evaluated in Beijing, Xianghe and Taihu three typical global aerosol monitoring network (AERONET) sites of China based on the observation data of AERONET and the surface albedo data of MODIS. 6S (Second Simulation of a Satellite Signal in the Solar) radiative transmission model was used. The results showed: (1) the PM2.5 mass concentration in three typical high pollution sites showed obvious seasonal variations, and the pollution was more serious in the autumn and in the winter than other season. In especial, the high values of PM2.5 mass concentration were mainly concentrated in January, February, November and December. (2)Compared with no aerosol, the interannual change of surface direct radiation caused by aerosol was obvious in each site. Affected by aerosol, the interannual change in daily average surface direct radiation in Beijing, Xianghe and Taihu stations was obviously increasing from 2001 to 2016. In especial, the maximum daily direct radiation was found in the Xianghe station (621.14W·m⁻²),followed by the Taihu station (743.29W·m⁻²) and the Beijing station (488.14W·m⁻²). (3) Affected by aerosol, the surface direct radiation in each station was reduced. Moreover, the effects of aerosol on the surface direct radiation in different stations were different. During the time of 2001−2016, the average surface direct radiation in Beijing, Taihu and Xianghe stations decreased by 32.29%, 24.01% and 15.07%, respectively. Among them, the aerosol had the greatest impact on the direct surface radiation of Beijing Station, followed by Taihu station and Xianghe station. (4) Over the recent 15 years, the aerosol surface radiation effect in Beijing,Xianghe and Taihu stations all increased.