Investigation Of The Detection Method Of Pollutant Flux By Scanning Lidar

The flux of atmospheric pollutants is the flow of pollutants per unit area per unit time.It is the physical parameter that characterizes the transport intensity of pollutants.It is a comprehensive parameter containing pollutant concentration and wind speed and direction information,with size and direction.It is important to assess the state of the atmosphere and the weather forecast for pollution.Therefore,the scanning lidar detection method for constructing pollutant flux has important practical significance and clear application background for studying the spatiotemporal distribution structure and transport mechanism of pollutants in the atmospheric boundary layer.This thesis takes the pollutant flux in the atmospheric boundary layer as the research target,based on the basic principle of atmospheric pollutant flux detection,based on the three-dimensional scanning lidar and coherent Doppler wind lidar experimental system,the spatial and time scale models are proposed.According to this model,a multi-data fusion model of pollutant flux is constructed,and then the horizon tal and vertical transport characteristics of pollutants on the space-time scale are calculated and analyzed.Firstly,the aerosol in the atmospheric boundary layer is detected by the scanning lidar in the vertical and three-dimensional cone scanning state,and the mass concentration is converted into the mass concentration according to the mathematical regression relationship between the aerosol extinction coefficient and the mass concentration,thereby analyzing the pollutant.High stratification and time-varying characteristics of mass concentration.Secondly,the Doppler wind lidar is used to continuously observe the atmospheric wind field,and analyze and verify the height and time stratification characteristics of the horizontal wind speed and direction.Taking the daily average pollutant concentration,the atmospheric wind field data is used as the only quantity to construct the spatial and temporal scale pollutant flux stratification calculation model,and based on the model,the pollutant flux in the area is estimated and analyzed.,space,and the value of wind speed and wind direction data combined with spatiotemporal scales for pollutant flux.Finally,the joint real-time observation of the scanning lidar and the wind lidar is realized,and the obtained pollutant concentration and atmospheric wind field data are respectively inverted,and the data matching fusion model of the pollutant mass concentration and the wind speed and direction data is used,including the inversion space,The pollutant fluxes of the two scales and the horizontal and vertical states;the spatial and time scale benchmarks are respectively set,and the vertical distribution structure of the pollutant concentration difference and the vertical flux transport characteristics on the space-time scale are analyzed.The detection and inversion of aerosol mass concentration in the atmospheric boundary layer by scanning lidar,the data space characteristics show the distribution law of concentration decreasing with height,and mainly concentrated in the height layer below 1km;the time scale change law depends on The atmospheric wind field further verified the feasibility of the concentration conversion formula and the space-time detection method.The continuous observation data of the atmospheric wind field shows that the horizontal wind speed upper layer is larger than the low-altitude layer,and the evening period is greater than the early period,which verifies the rationality and universality of the stratification theory.Based on the flux fusion model and experimental results,it is concluded that the influence of wind field information on pollutant flux is dominated by wind speed and wind direction.The fusion results of pollutant fluxes show that the vertical and horizontal transport intensities on the spatial scale are characterized by high stratification,low-altitude intensity and height,and the vertical transport direction is downward.On the time scale,the horizontal transport intensity must be integrated with the pollutant concentration difference and horizontal wind speed.The wind direction is combined and analyzed,and the conveying direction is the horizontal wind direction.The space-time conveying mechanism of pollutants is initially explored.