A Study Of Aerosol Optical Characteristics And Its Physical And Chemical Characteristics In Nanning

Nanning,the capital city of Guangxi is the permanent venue of China-ASEAN Expo,which held every year.So,its atmospheric environmental problem has been noticed and cared about.Aerosols made up of suspension of liquid and solid particles in the atmosphere,which has a greater influence on climate and environment,and has become a research hotspot.On the one hand,Aerosols can directly or indirectly influent the physical and chemical process of the atmosphere,which affect the radiation budget and energy balance of earth-atmosphere system.On the other hand,aerosols also have a serious impact on the living environment and human health.Howerver,there were some considerable uncertainties in estimating aerosols effects due to poor understanding of aerosol optical characteristics.In this paper,CE-318 multi wavelength sun photometer is used for a long-term,continuous observation of atmospheric aerosol optical characteristics in the study region.Based on the data of CE-318 multi wavelength sun photometer and ground-based data,aerosol optical characteristics and its physical and chemical characteristics were analyzed,and the atmospheric aerosol types in the study region were recognized.Secondly,the different meteorological factors and air quality data how to affect the aerosol optical characteristics and its physical and chemical characteristics were also analyzed.Finally,multiple linear regression model was built in inversion of the concentration of PM_2.5 using CE-318 data,meteorological data and MODIS aerosol product.The main conclusions in this paper are as follows:?1?Atmospheric aerosol extinction characteristics are different in different wavelengths,and the general trend is increased?decreased?when the wavelength is increased?added?.The seasonal variation of aerosol optical depth in Nanning was distinguished with high values in autumn,spring and winter,and relatively low values in summer.The seasonal variation of Angstrom wavelength exponent values from large to small in turn for autumn,winter,spring and summer.The seasonal variation of Angstrom turbidity index was distinguished with high values in autumn,spring and winter,and relatively low values in summer.The change trends of atmospheric aerosol optical characteristics were affected by the monsoon seasons and climate change impact in this study region.The atmospheric aerosol type of Nanning is the mixture of the Industry-urban aerosol and the maritime aerosol with the strong scattering by analyzed the Angstrom wavelength exponent frequency distribution and single scattering albedo,considers in the geographical environment of study region.?2?During the haze events,the aerosol optical depth,Angstrom wavelength exponent,Angstrom turbidity index and single scattering albedo increased obviously,which was indicated the air pollution was more serious by the smaller spatial scale and the strong scattering atmospheric aerosol particles.Due to the increase of human activities and traffic load,the aerosol optical depth and Angstrom wavelength exponent of no-working days are larger than the working days,and the smaller spatial scales aerosol particles were the major part of aerosol in Nanning.?3?Based on the air quality monitoring data such as PM_2.5/PM₁₀ and O₃/SO₂/NO₂/CO,the variations of aerosol optical characteristics and its physical and chemical characteristics in Nanning were analyzed.In the same time,those change characteristics and the correlations were also analyzed.The seasonal variation of the PM_2.5 mass concentration and the PM₁₀ mass concentration were: autumn>winter>spring>summer.The O₃ mass concentration in the seasonal variation was: summer>spring>autumn>winter.The SO₂ mass concentration in the seasonal variation was: winter>spring>summer>autumn.The NO₂ mass concentration and CO mass concentration in the seasonal variation were: winter>autumn>spring>summer.During the observation period,the frequency distribution of the mass concentration of O₃/SO₂/NO₂/CO showed anunmoral distribution.Correlation between the concentrations of O₃/SO₂ and PM_2.5 high than the correlation of O₃/SO₂ and PM₁₀,which indicated the influence of O₃/SO₂ on PM₁₀ was relatively large;Correlation between the concentration of NO₂/CO and PM_2.5high than the correlation of NO₂/CO and PM₁₀,which indicated the influence of NO₂/CO on PM_2.5 was relatively large.However,the change of mass concentration of SO₂ and NO₂ had the greatest influence on the PM_2.5 and PM₁₀ mass concentration.There was a negative correlation between the meteorologicalfactors and PM_2.5/ PM₁₀.?4?Good correlation was found between the atmospheric aerosol optical depth measured by CE-318 multi wavelength sun photometer and MODIS aerosol optical depth product.After using CE-318 AOD to correct the MODIS AOD,the correlation coefficient between AOD and PM_2.5 mass concentration increased significantly.The correlation increased further with multivariate regression with meteorological factors,then ultimately determine the MODIS AOD and PM_2.5 inversion model was Y=34.158X1-6.401X2-0.507X3-21.351X4+276.204,which R-Squared was 0.689.It can be concluding that MODIS AOD can be utilized to retrieve PM_2.5 mass concentration in Nanning.