Study Of Aerosol Properties In The Boundary Layer Over Wuhan Based On Ground-based Lidar

As global economic development,population expansion,and industrial activity increase,more and more anthropogenic emissions enter the atmosphere,causing climate warming and deteriorating air quality.The impact of aerosols on climate and environment cannot be underestimated.The effects of aerosols on the global atmospheric environment are mainly manifested in three aspects: First,aerosols have absorption and scattering properties,which can affect global and regional climate change by changing the solar radiation.At the same time,aerosols can also cause environmental problems,such as regional haze and dust pollution,which adversely affect human health.Finally,aerosols can act as cloud condensation nuclei that affect the water cycle of the atmosphere.Therefore,long-term accurate observation and research on the content and characteristics of atmospheric aerosols is essential.Atmospheric detection lidar has been widely used in atmospheric environment research because of its high temporal and spatial resolution and its ability to efficiently acquire the optical and physical properties of aerosols.Based on the long-term observation data of the ground-based atmospheric detection lidar in Wuhan,the paper studies the changes of atmospheric boundary layer height,the aerosols properties and pollutants in the boundary layer.At the same time,the multi-source observation data of local environmental monitoring stations and satellites are combined to reveal the mechanism of winter haze pollution in Wuhan.The main research contents of this paper are as follows:1)Development of ground-based atmospheric detection lidar.To obtain more atmospheric aerosol parameters,a dual-wavelength polarization atmospheric detection lidar system was designed and developed independently,which can effectively obtain aerosol color ratio and depolarization ratio.Moreover,this system was coaxial design,greatly reducing the impact of near-ground signal overlap factor.At the same time,channel calibration and data correction were performed on the system.2)Research on the lidar atmospheric boundary layer height inverse algorithm.In order to overcome the influence of complex atmospheric states on the boundary inversion,a method for solving the boundary layer height based on particle characteristics is proposed.Firstly,based on the problem that the multi-level aerosol affects the inaccuracy of the boundary layer height,the two-dimensional distribution of atmospheric particles in the vertical direction is calculated by using the color-to-color ratio information and the depolarization ratio information of the ground-based lidar inversion,and the particles are searched.The method of maximum difference is to solve the influence of multi-level aerosol in solving the boundary layer height.Then,based on the problem that the residual layer aerosol affects the inaccuracy of the boundary layer height,the information of the color ratio information and the backscatter ratio of the ground-based lidar inversion is proposed,and the aerosol layer and the free atmosphere are distinguished by particle clustering.Invert the height of the boundary layer to effectively overcome the effects of residual layer aerosols.3)Study of aerosol characteristics in boundary layer over Wuhan area.To better understand the impact of aerosols on human life,it is essential to long-term observation of aerosols.Based on the long-term lidar observation data,the optical and physical properties of aerosols in the boundary layer over Wuhan are analyzed,and the two-dimensional distribution of aerosol color ratio and depolarization ratio is obtained.Further,the aerosol physical parameters were statistical analysis.A classification standard of pollution levels was proposed based on aerosol color ratio.4)Aerosol characteristics under different pollution periods.Based on the observation data over Wuhan site,the aerosol characteristics over Wuhan during different pollution periods were analyzed.Moreover,the effects of meteorological parameters such as temperature,humidity,wind and pressure on the optical properties of aerosols were also studied.Finally,the interaction mechanism between black carbon aerosol and boundary layer during heavy pollution period is analyzed.5)Study of winter haze pollution over Wuhan area.According to the ground-based observation data,the concentrations and characteristics of aerosol under different pollution periods were analyzed.Then,the CALIPSO satellite was used to analyze the regional air pollution and the atmospheric aerosol category.Finally,the backscatter trajectory model was used to simulate the atmospheric air mass.The trajectory of the motion,the source of the pollutants.Through comprehensive data,the characteristics and sources of aerosols in the haze event in the central region were studied,and the formation mechanism of pollution in Wuhan was revealed.