Study On Detection Of Atmospheric Aerosols By Airborne High Spectral Resolution Lidar

Aerosols only make up a small part of the atmosphere,but they have important effects on atmospheric change,climate change,and human health.Therefore,it is very important to observe aerosols with high spatiotemporal resolution,high accuracy and real time.Among many aerosol observations instruments,lidar,as an active remote sensing measurement tool,has been rapidly developed due to its unique advantages in terms of monochromaticity,directivity,coherence,and brightness.Its high spatiotemporal and vertical profile measurement characteristics have also made lidar widely used in environmental detection and atmospheric monitoring.Compared with the traditional Mie scattering lidar,the High Spectral Resolution Lidar?HSRL?uses a narrow-band optical filter to separate the molecular Rayleigh scattering signal from the aerosol Mie scattering signal.HSRL can directly invert optical parameters such as aerosol backscattering coefficient and extinction coefficient without assuming the lidar ratio.Therefore,the accuracy of the inversion aerosol optical parameters is improved.This paper is based on a set of developed iodine molecular filter airborne HSRL system,which realizes the high-precision detection of atmospheric aerosols,and applies this system to airborne high-altitude detection for continuous observation in a wide range of multiple areas.In this paper,after the entire system has been built and calibrated,the ground verification experiment is first carried out on the HSRL system,and a MPL is used to compare and verify its simultaneous observation.The results show that,in the case where MPL cannot penetrate the 3km high cloud layer,the HSRL system can easily detect the 3km two-layer cloud structure and continue to detect higher altitudes.At the same time,the aerosol inversion results of the two lidars showed good consistency,with a relative error of less than 10%.This HSRL system was then carried on a Y-8 transport aircraft,and several flight tests were carried out.Several observational tests under different degrees of polluted weather,different altitudes and different types of surface were completed,and a large number of valuable data was detected and saved.At the same time,the improved HSRL inversion algorithm was used to invert the detection data,and the optical parameters such as aerosol backscattering coefficient,extinction coefficient,depolarization ratio and lidar ratio under different surface types were compared and analyzed.Based on the existing aerosol classification methods,preliminary classification of aerosols in different regions was done.In addition,the aerosol characteristics at different dates are analyzed by combining a solar photometer,an atmospheric pollutant transport and diffusion trajectory model and satellite data.The results show that in the urban factory area,the aerosol type is mostly urban pollution type and soot type aerosol,and the vertical distribution changes greatly,and the extinction coefficient exceeds 1.2 km^-1.The types of aerosols in the ocean and mountain areas are relatively single and the vertical distribution changes little.The extinction coefficient is concentrated between 0.2 and 0.8 km^-1,but it is also affected by the diffusion of urban pollutants;And the distribution of aerosols is affected by meteorological conditions such as wind and weather pollution processes.The optical characteristics of aerosols in the same area on different dates are also affected by factors such as the transport and diffusion of atmospheric pollutants.This test fully verified the excellent and reliable aerosol detection performance of the airborne HSRL system.This paper is of great significance to the use and promotion of airborne HSRL,and it is of great research significance and value to China's ongoing spaceborne lidar development and satellite-to-ground comparison and verification after launch.