Trends in aerosol optical properties over Eastern Europe based on MODIS-Aqua

This study provides characteristics of aerosol columnar properties,measured over ten countries in Eastern Europe from 2002 to 2019.Aerosol optical depth(AOD)and Angstrom exponent(AE)were obtained with the Moderate Resolution Imaging Spectroradiometer(MODIS)Collection 6.1 merged Dark Target and Deep Blue aerosol product.The product is validated using ground-based Aerosol Robotic Network(AERONET)situated at Minsk,Belsk,Moldova and Kyiv.The results showed that 76.15%of retrieved AOD data are within the expected error.It was established that 64.2%of AOD points are between 0 and 0.2 and 79.3%of all AE points are over 1.Mean AOD values in the region vary from 0.130±0.04(Moldova)to 0.193±0.03(Czech Republic)with mean value in the region 0.162±0.05.Seasonal mean AOD(AE)values were at the maximum during the summer from 0.231±0.05(1.482±0.09 in winter)to minimum 0.087±0.04 during the winter(1.363±0.17 in summer).Gradual AOD reduction is observed in all countries with annual trend from-0.0050(Belarus)to-0.0029(Russia).Finally,the relationship between AOD and AE was studied to classify various aerosol types and showed seasonal non-uniformity of their contribution depending on variation in sources.The entire region is under significant impact of various aerosol types,including clean continental(CC),mixed(MX)and anthropogenic/burning(AB)aerosols types that are at 59.77%,24.72%,and 12.97%respectively.These results form an important basis for further regional studies of air quality and distribution of sources of pollution.