Quantitative Analysis Of Spatial-temporal Characteristics And Driving Forces Of Terrestrial Aerosols In China In Nearly A Decade

Atmospheric aerosols affected the Earth's radiation balance by absorbing and scattering solar radiation.At the same time,aerosol particles,as condensation nodules of clouds,could affect the optical properties and cloud amount of clouds,and then produce indirect effects on precipitation and water cycle.The problem of aerosol pollution was particularly prominent.It was urgent to study the space-time characteristics and driving forces of aerosols under the background of air pollution prevention and control in China.Aerosol Optical Depth(AOD),as an important physical quantity to characterize atmospheric turbidity,was not only one of the key indicators to measure aerosol,but also a key factor to determine the climate effect of atmospheric aerosol radiation.Remote sensing technology was widely used,which can support aerosol monitoring with large-scale,multi-channel and high spatial-temporal resolution.MODIS(Moderate-resolution Imaging Spectrometer)AOD product data have been widely used in the study of global and Regional Aerosol spatial-temporal distribution and change.In recent years,China's economy has shown a rapid development trend.China's industrial and agricultural production activities are very active.In these production activities,a lot of aerosol particles were discharged into the atmosphere.The sources of these particulates,regional and regional differences between large,causing more environmental problems.Therefore,it was necessary for us to make a macro analysis of the atmospheric environment in China.Guided by the theories and methods of geography,this study selected MODIS Aqua C006 aerosol product data from 2008 to 2017 with the help of RS technology and mathematical methods to analyze the temporal variation regularity and spatial pattern distribution characteristics of land aerosol optical thickness in recent ten years in China.With the Hu Line as the boundary,the arid region of Northwest China and Beijing-Tianjin-Hebei region were selected as typical regions to analyze the spatial and temporal characteristics of AOD.The main driving factors of aerosol optical thickness in typical areas were determined by principal component analysis,and then the quantitative model of AOD driving force was established.The specific conclusions were as follows:(1)The average annual and seasonal distribution characteristics of China's terrestrialAOD are consistent with the characteristics.From 2008 to 2017,the overall trend showed a downward trend with little change.The high-value areas were Beijing-Tianjin-Hebei region,Central China region,Yangtze River Delta region,Pearl River Delta region and Tarim Basin.The low-value areas were Qinghai-Tibet Plateau,Yunnan-Guizhou Plateau,Inner Mongolia Plateau,etc.The spatial and temporal distribution of AOD showed strong seasonal characteristics,with the highest AOD in spring and the lowest in autumn.(2)The average annual AOD distribution in the arid regions of Northwest China showed obvious regular distribution characteristics from 2008 to 2017;the aerosol values in spring and summer in the arid regions of Northwest China were higher.The Tarim Basin was a high-value area,and the Altay area was a low-value area.The AOD value in the Beijing-Tianjin-Hebei region was always high in the past ten years,and the aerosol concentration in the southern region was high in all seasons.The AOD value in the Beijing-Tianjin-Hebei region was higher in summer than in winter than in winter.(3)Determine the driving force index elements and analyze the driving force indicators of the arid regions in the northwest and the Beijing-Tianjin-Hebei region.Taking AOD(y)as the dependent variable,precipitation(x1),GDP(x2),NDVI(x3)and LST(x4)are the independent variables in the arid regions of Northwest China,and LST(x1)and GDP(x2)in the Beijing-Tianjin-Hebei region.Precipitation(x3)and wind speed(x4)are independent variables.A multivariate regression model is established to quantitatively analyze the regional scale driving force.The model fitting degree in the arid area of Northwest China was 77%,and the model fitting degree in the Beijing-Tianjin-Hebei region was 81%.This study had practical guiding significance for scientific prediction and effective control of atmospheric particulate matter in China,and hopes that this study can provide a scientific basis for China's climate change research,climate change response policies and actions,and climate negotiations.