Study On Active And Passive Remote Sensing Inversion Of Cirrus Optical Thickness

Cloud optical thickness(COT)is one of the important optical parameters cirrus clouds,affects the global radiation budget and climate change,is widely used in atmospheric science,military and other fields of physics cloud optical properties is complex,the accurate inversion of the optical thickness is difficult to achieve.The rapid development of modern main passive remote sensing technology,for the volume cloud optical thickness inversion provides a new way of thinking.In this paper,based on the passive remote sensing technology,combining with the foundation CE318 sun radiometer observation data inversion of cloud optical thickness is studied,mainly including the following several aspects:Firstly,using the passive remote sensing inversion roll cloud optical thickness.Based on a roll cloud optical thickness inversion theory,using the vector radiative transfer model RT3 and MODIS sensor data,build a look up table inversion volume cloud optical thickness,and compared with the official data consistency analysis,then select the same area within the scope of different period data,spatial and temporal distribution of cloud optical thickness are discussed.The results show that the matching degree of the cirrus optical thickness inversion is 97% with the MODIS official data,and the average error of the temporal and spatial distribution of cirrus optical thickness is less than 0.16,which verifies the effectiveness of the cirrus optical thickness inversion by constructing the look up table.Secondly,the optical thickness of cirrus is retrieved using active remote sensing technology.Based on the theoretical basis of cloud measurement by active remote sensing satellite CALIPSO,the characteristics of cloud products and the spatial matching theory of LIDAR CALIOP and MODIS sensor,the vertical direction parameters of cirrus optical thickness are retrieved by using MODIS and CALIOP vertical direction observation data in the same space range.The CALIOP lidar complements the cloud base data of cirrus and marks the location of multi-layer and single-layer clouds in space.In addition,according to the results of active and passive satellite data matching,the variation trend of MODIS and CALIPSO data observed in the same latitude is basically the same.Finally,the effect of aerosol on cirrus optical thickness inversion is analyzed,and the method of cirrus optical thickness inversion is improved by using CE318 solar radiometer observation data.The statistical analysis of the relationship between AQI and cirrus cloud optical thickness inversion results shows that the smaller the AQI value is,the better the inversion effect is.Then,considering the influence of aerosol optical parameters on cirrus COT inversion results,the cirrus reflectivity under different aerosol types,different COT and aerosol optical thickness(AOD)is calculated.The results show that the single scattering albedo and AOD affect the cirrus optical thickness inversion.The accuracy of the improved cirrus optical thickness inversion is increased by 4.5% on average by using aerosol parameters measured at CE318 based on Guilin monitoring site.The research work in this paper has realized the simple and effective inversion of cirrus optical thickness,which provides a reference for the application of active and passive remote sensing technology to the inversion of cirrus optical parameters,and also provides support for the inversion of cirrus optical characteristics in Guilin and other areas.