| Atmospheric aerosol is a multiphase system composed of various liquid and solid particles suspended in the atmosphere medium and the atmosphere,and the diameter is generally between 10-3102?m.Although the proportion in the atmosphere is small,it's unique physical and chemical reactions in the atmosphere can affect changes in atmospheric radiation,climate,and atmospheric environment.Aerosol particles with a diameter of less than 2.5?m are called PM2.5,which can directly enter the human lungs,thus having a great impact on health.However,due to the small number of monitoring stations and uneven distribution,the monitoring of PM2.5 concentration is not timely enough and the scope is small.Therefore,the spatial and temporal distribution characteristics of aerosol optical thickness are obtained by using satellite remote sensing data inversion,which further inverts the spatial distribution characteristics of PM2.5concentration,which is beneficial to make up for the small monitoring range of the measured station and the large-scale analysis of the concentration distribution of particulate matter.Taking Jiangxi Province as the research object,this paper uses the MODIS satellite data and the terrestrial aerosol dark pixel method to invert the Aerosol Optical Depth?AOD?in Jiangxi Province from 2003 to 2017 for 15 years,and utilizes MODIS aerosol products.Accuracy verification of the inversion results shows that the inversion AOD accuracy is better.On this basis,the temporal and spatial variation characteristics of AOD in Jiangxi Province in the past 15 years were analyzed,and the factors affecting AOD distribution were analyzed.Finally,the optimal fitting model of PM2.5 was constructed by AOD.The main results are as follows:?1?The spatial distribution of aerosols in Jiangxi Province during the past 15 years from 2003 to 2017 is characterized by a“U”-shaped distribution,that is,the AOD values around the mountainous areas in the east and west are lower,and the AOD values in the central and northern plains are higher.?2?Analyze the mean value of AOD in 15 years and find that it shows an overall rising fluctuation.Among them,the highest AOD value in 2007 was 0.4655,and the lowest AOD value in 2005 was 0.1842.According to the four seasons,the change of AOD value in Jiangxi Province in the past 15 years is expressed as:spring>summer>autumn>winter.A comparison of AOD values for each month in 15years showed that the highest in May,the AOD value was 0.6779,the lowest in December,and the AOD value was 0.1522.?3?Analysis of the influencing factors found that there is a significant negative correlation between AOD and altitude and slope,that is,with the increase of altitude and slope,the AOD value is significantly reduced;the trend line between AOD and precipitation is significantly opposite,ie The higher the AOD value,the lower the precipitation.There is also a significant negative correlation between AOD and EVI.That is,the higher the vegetation coverage,the lower the AOD value.The average AOD value of different land use types is from low to high.For:forest land<irrigation grass<cultivated land<water body<built-up area.There is a significant positive correlation between the population density and AOD in Jiangxi Province,that is,the greater the population density,the higher the AOD value.?4?After obtaining the average value and distribution of AOD in Jiangxi Province in the 15 years from 2003 to 2017,narrow the scope to each city in Jiangxi Province,and construct an inversion model of AOD value and PM2.5.It is found that after the vertical-humidity correction of AOD,two The relevance of the person is higher.After obtaining the optimal inversion model of PM2.5 in each city,the AOD values of each city are brought into the inversion model to obtain the distribution map of PM2.5 in each city.After splicing,the PM2.5 concentration distribution map of Jiangxi Province is obtained.The 6S clothing transmission model is used to establish the aerosol look-up table for summer and winter in Jiangxi province's unique geographical location and climate environment,and the aerosol optical film thickness in Jiangxi Province is retrieved by using the terrestrial aerosol dark pixel method.The spatial and temporal distribution characteristics of aerosols in Jiangxi Province from 2003 to 2017 were obtained,and the distribution map of PM2.5 concentration in Jiangxi was obtained.In this process,the causes of natural environment change and urban development are analyzed to provide a reference for the pollution of human activities to the atmospheric environment.Provide more scientific basis and means for improving the atmospheric environment and air quality. |
PDF Full Text Request