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 Res...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.展开更多
The accuracy of MODIS aerosol products from the NASA Terra Satellite is validated in comparison with the results of sun-photometer observations in Beijing and Hong Kong. By analyzing the MODIS aerosol products within ...The accuracy of MODIS aerosol products from the NASA Terra Satellite is validated in comparison with the results of sun-photometer observations in Beijing and Hong Kong. By analyzing the MODIS aerosol products within the period of August 2000 to April 2003, it is believed that human activities are the main source of aerosols in the eastern part of China. This is based on the facts that all areas with relatively high values are consistent with regions of dense population and fast economic development, such as the North China Plain, the Sichuan Basin and the Pearl River Delta. It is also supported by the distribution of 舗gstr鰉 exponents showing that most aerosols in the eastern part of China are closely related to human activities, excepting the strong sandstorm episodes occurring in spring, fall and winter. In contrast to developed countries, the 舗gstr鰉 exponent of urban area in China is lower than its surroundings, indicating that the contribution of local floating dust and soot attributed to human activities is significant. Results presented in this paper provide important data for further research on climatic change and environmental study.展开更多
Aerosol optical depths (AODs) from MODIS and MISR onboard the Terra satellite are assessed by comparison with measurements from four AERONET sites located in northern China for the period 2006-2009. The results show t...Aerosol optical depths (AODs) from MODIS and MISR onboard the Terra satellite are assessed by comparison with measurements from four AERONET sites located in northern China for the period 2006-2009. The results show that MISR performs better than MODIS at the SACOL and Beijing sites. For the Xianghe and Xinglong sites, MODIS AOD retrievals are better than those of MISR. Overall, the relative error of the Angstrom exponent from MISR compared with AERONET is about 14%, but the MODIS error can reach 30%. Thus, it may be better to use the MISR Angstrom exponent to derive wavelength-dependent AOD values when calculating the aerosol radiative forcing in a radiative transfer model. Seasonal analysis of AOD over most of China shows two main areas with high aerosol loading: the Taklimakan Desert region and the southern part of North China and northern part of East China. The locations of these two areas of high aerosol loading do not change with season, but the AOD values have significant seasonal variation. The largest AOD value in the Taklimakan appears in spring when the Angstrom exponents are the lowest, which means the particle radii are relatively large. Over North and East China, the highest aerosol loading appears in summer. The aerosol particles are smallest in summer over both high-AOD areas.展开更多
基金financially supported by the National Key R&D Program of China(Grant No.2017YFB0504203)the China Postdoctoral Science Foundation Funded Project(Grant No.2018M633605)the Postdoctoral Fund of Lanzhou Jiaotong University(Grant No.2018BH03001)。
文摘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.
基金supported by the grant NSFC/HKUST36 and the National Natural Science Foundation of China(Grant No.1999045700).
文摘The accuracy of MODIS aerosol products from the NASA Terra Satellite is validated in comparison with the results of sun-photometer observations in Beijing and Hong Kong. By analyzing the MODIS aerosol products within the period of August 2000 to April 2003, it is believed that human activities are the main source of aerosols in the eastern part of China. This is based on the facts that all areas with relatively high values are consistent with regions of dense population and fast economic development, such as the North China Plain, the Sichuan Basin and the Pearl River Delta. It is also supported by the distribution of 舗gstr鰉 exponents showing that most aerosols in the eastern part of China are closely related to human activities, excepting the strong sandstorm episodes occurring in spring, fall and winter. In contrast to developed countries, the 舗gstr鰉 exponent of urban area in China is lower than its surroundings, indicating that the contribution of local floating dust and soot attributed to human activities is significant. Results presented in this paper provide important data for further research on climatic change and environmental study.
基金supported by the National Basic Research Program (2012CB955302)the National Natural Science Foundation of China (41105019 and 41175042)+1 种基金the Specialized Research Fund for Doctoral Program of Higher Education (20110211120021)the Fundamental Research Fund for Central Uni versities (lzujbky-2011-4)
文摘Aerosol optical depths (AODs) from MODIS and MISR onboard the Terra satellite are assessed by comparison with measurements from four AERONET sites located in northern China for the period 2006-2009. The results show that MISR performs better than MODIS at the SACOL and Beijing sites. For the Xianghe and Xinglong sites, MODIS AOD retrievals are better than those of MISR. Overall, the relative error of the Angstrom exponent from MISR compared with AERONET is about 14%, but the MODIS error can reach 30%. Thus, it may be better to use the MISR Angstrom exponent to derive wavelength-dependent AOD values when calculating the aerosol radiative forcing in a radiative transfer model. Seasonal analysis of AOD over most of China shows two main areas with high aerosol loading: the Taklimakan Desert region and the southern part of North China and northern part of East China. The locations of these two areas of high aerosol loading do not change with season, but the AOD values have significant seasonal variation. The largest AOD value in the Taklimakan appears in spring when the Angstrom exponents are the lowest, which means the particle radii are relatively large. Over North and East China, the highest aerosol loading appears in summer. The aerosol particles are smallest in summer over both high-AOD areas.
