山东气溶胶光学厚度时空分布及其与地面大气污染物质量浓度的相关性分析

基于卫星的气溶胶光学厚度(aerosol optical thickness,AOT)是研究大气污染程度及时空变化的重要参考,由于大气污染物排放特征、地理和气候背景不同,不同区域AOT的时空分布及其与地面大气污染物质量浓度的相关性存在一定的差异.选取了2017年7月-2020年7月山东89个国家环境空气质量监测站数据、...

Study on spatial and temporal distribution of AOT and its correlation with mass concentrations of ground-level atmospheric pollutants in Shandong

The satellite-based aerosol optical thickness(AOT)is a major reference for studying air pollution and its spatial and temporal variations.As a result of distinct air pollutant emission,geography,and climate background,the spatial and temporal distribution of AOT and its correlations with mass concentrations of ground-level pollutants are different in different areas.In this study,selected data of 89 national environment monitoring stations in Shandong from July 2017 to July 2020,Himawari-8/9 AOT products issued by Japan Aerospace Exploration Agency(JAXA),and ERA5 reanalysis data issued by European Center for Medium-Range Weather Forecasts(ECMWF)are analyzed to explore the spatial and temporal distribution of AOT in Shandong and its correlations with mass concentrations of ground-level pollutants.The results are shown below.1)There are two major low AOT areas in Shandong,distributed around the mountainous areas of central Shandong and Jiaodong Peninsula with an extension to the east coast,and the distribution of low AOT areas presents few seasonal variations;high AOT in Shandong mainly covers areas in the west and south of Shandong which are in conjunction with other provinces and areas from southern Bohai to the coast of Laizhou Bay,which is noteworthy when analyzing the interprovincial transport of aerosol.The distribution of high AOT areas is different in different seasons.2)The diurnal variation of AOT in Shandong,which declines from the peak at 08:00,goes up at 11:00,and reaches its daily maximum(0.608)at 14:00,has a bimodal distribution;the diurnal variation of AOT is quite different with that of fine particulate matter(PM2.5)and O3,which is an important factor affecting the correlations.For monthly distribution,there are two peak values obtained in July(0.648)and October(0.622),while AOT in February has the minimum value.There is to some extent contradictory seasonality between AOT and mass concentrations of ground-level pollutants.3)In general,the correlations between AOT and mass concentrations of ground-level pollutants,such as PM2.5 and O3,are weak,while June sees the lowest and January the highest correlation coefficient values.AOT has the highest correlation with mass concentrations of pollutants between 15:00 and 17:00 and the lowest correlation coefficient at 10:00.This research shows it is difficult to quantitatively reflect the distribution of ground-level pollutants only based on AOT,and more factors need to be considered in monitoring and analyzing ground-level pollutions via satellite remote sensing.