Synchronous Observation And Inversion Of Ozone And Aerosol By UV Multi-wavelength Lidar

In recent years,ozone pollution shows an increasing trend,and combined air pollution in Beijing-Tianjin-Hebei region is becoming increasingly serious.The vertical range resolution of ozone and aerosol can be obtained simultaneously by UV multi-wavelength lidar.Wangdu County,Baoding City,Hebei Province is located in the central part of Beijing-Tianjin-Hebei region,so it is of great scientific and practical significance to study the ozone and aerosol pollution events in this region based on UV multi-wavelength lidar.In this paper,firstly,based on the echo data of 276,287 and 299 nm wavelengths of UV multi-wavelength lidar,the ozone concentration profiles retrieved by dual-wavelength and three-wavelength dual-differential absorption algorithms are compared.Simultaneous aerosol observation was carried out with the aid of a 396 nm Mie scattering lidar,which was not affected by ozone absorption.The results show that the error fluctuation and value of ozone concentration caused by the backscattering term are the largest in the dual-wavelength inversion algorithm,and the maximum mean error of ozone concentration is 16μg/m3.Therefore,when the dual-wavelength differential absorption algorithm is used to invert ozone concentration in haze days,the influence of atmospheric interference term cannot be ignored.Compared with dual-wavelength algorithm,three wavelengths double difference absorption algorithm can reduce the influence of part of aerosols.Based on the inversion of ozone concentration,the extinction coefficients of the three wavelengths of the lidar were eliminated by the ozone absorption part,and the aerosol extinction coefficients of each wavelength were obtained.And aerosol parameters inversion results and 396 nm of extinction coefficient and AERONET AOD data consistency is better.Finally,the typical pollution weather in Wangdu County was analyzed based on the inversion results of UV multi-wavelength lidar,surface air quality data,MERRA-2 reanalysis data,sounding data and HYSPLIT backward trajectory analysis.The results show that the boundary layer height is less than 300 m during the ozone heavy pollution event.By inversion of ozone concentration at 300 m and AOD above 300 m,it is found that the change trend of the two is opposite,and AOD’s inhibition effect on UV radiation is most obvious at noon.During the period of heavy pollution,surface inversion and calm wind weather aggravate the pollution.During the observation period,the air pollution in Wangdu County was not only affected by the local pollution emission,but also affected by the transport of pollutants from the northwest direction.This study can provide important reference for monitoring and prevention of combined air pollution.