The Study On The Characteristics Of Aerosols Based On Local Lider Signal Parameters

This article mainly discusses the working principle of satellite-borne lidar and gives a brief introduction to the CALIPSO satellite system.The CALIOP lidar,one of its payloads,is introduced in detail,including satellite data processing and data acquisition.The data of Level1and Level2 of CALIPSO satellite are selected as the key points in this thesis.The aerosol distribution in Tianjin area is analyzed and studied.All of the satellite data in this article come from NASA's CALIPSO official website,while the required Level1 and Level2 data are downloaded,while the selected data is initially screened.The total attenuation backscattering coefficient and 532 nm vertical channel backscattering coefficient of 532nm and 1064nm channels in Level 1 data were extracted,and then the corresponding volume depolarization ratio and color ratio were calculated.With the total attenuation backscattering coefficient of 532nm,the volume depolarization Ratio and color ratio to analyze the 2014 annual atmospheric aerosol distribution in Tianjin.Divide the different heights 0²km,2⁴km,4⁶km,6⁸km,8¹0km further analysis.The results of this paper show that:1)The scattering ability of the atmosphere in Tianjin decreases with the increase of altitude.Aerosol mainly concentrated in the near-surface height?0²km?,aerosol particles had a higher degree of regularity and larger particle size.Aerosols distributed more evenly in the 2¹0km altitude layer,The particle size is also smaller.By comparing the different seasons in Tianjin,it is found that the distribution of seasons is more obvious,and aerosol scattering ability is stronger in winter and spring than in summer and autumn.When dealing with the secondary data,after screening the data by using the relevant screening quality parameters,the typical weather in Tianjin area is compared and analyzed by means of extinction coefficient,volume depolarization ratio and color ratio,and several typical weather gas Vertical profile of sol,analyzed its distribution characteristics,sources of pollutants and so on.It is found that there are obvious differences in the distribution of aerosols in different weather,different layers of pollution will make the aerosols different layers;extinction coefficient of different degrees of pollution in the numerical and height distribution are also significantly different Aerosol particles of different pollutants vary greatly in size and regularity.Finally,according to the definition of aerosol optical thickness,the program was written by Matlab and the extinction coefficient was integrated to get the aerosol optical thickness.To explore the correlation between the aerosol optical thickness and PM₁₀ concentration,linear,unary quadratic,logarithmic,Power and index five types of the fit between the two.it was found that the aerosol optical thickness calculated by the CALIPSO satellite data was inversely proportional to PM10 Good correlation,and no matter the year or sub-seasons,the quadratic model of the correlation coefficient values are the largest.Through the analysis of aerosol properties in Tianjin,aerosol characteristics and weather have certain laws,to a certain extent,can affect the atmospheric changes,characterization of air quality.It also shows that the aerosol optical thickness obtained from CALIPSO secondary data can well reflect the degree of atmospheric pollution and has higher accuracy.