Detection Of Atmospheric Boundary Layer Height Based On The Scheimpflug Lidar Technique

Nowadays,with the development of science and technology and the acceleration of industrialization process,air pollution is becoming more and more serious.The big issue in atmospheric environmental governance has become difficult in the world.And the atmospheric environmental governance is to do with the study of atmospheric boundary layer structure.The atmospheric boundary layer interacts with the ground,the diurnal variation of the atmospheric boundary layer height is the result of the exchange of energy and momentum between the ground and the atmosphere.The atmospheric boundary layer height varies from several hundred meters to one or two kilometers.The height of the atmospheric boundary layer determines the diffusion range of aerosols or atmospheric molecules.Therefore,the atmospheric boundary layer height is not only an important feature of atmospheric boundary layer structure,but also an important parameter in the study of climate model and weather forecast.The emergence of lidar detection methods breaks through the difficulties of traditional methods in detecting boundary layer structure.Lidar plays a breakthrough role in the detection of atmospheric boundary layer structure.In this paper,firstly,the concepts of aerosol,atmospheric boundary layer and atmospheric boundary layer height,as well as the background and significance of lidar research are introduced respectively.Then the current situation of lidar inversion of atmospheric boundary layer height at home and abroad is introduced,which including different kinds of applications of lidar and calculation methods of atmospheric boundary layer height.Then in order to obtain the change of atmospheric boundary layer height in Dalian area,the backscattering signals of lidar reflected from aerosols are collected by SLidar system.Several commonly used inversion algorithms of boundary layer height are introduced,including gradient method,curve fitting method and wavelet covariance method,and their inversion performances are analyzed.In order to verify the feasibility of the wavelet covariance method in SLidar system,two experiments were carried out.A set of polarized lidar system was used to carry out the experimental detection in Dalian university of Technology in the sunny weather from May 1 to May 2,2017.The height of atmospheric boundary layer during the measurement period was obtained by using the wavelet covariance method from the detected backscattering signals.In order to further verify the feasibility of retrieving the height of atmospheric boundary layer on SLidar system by wavelet covariance method,a portable low-cost Mie-scattering SLidar system was used to carry out continuous measurements from 21 August to 28 August 2018.In order to eliminate the influence of cloud layer on the inversion of boundary layer height,a quality control algorithm based on wavelet covariance method was used while the signal was declouded.Through cloud processing and quality control algorithm,the height of atmospheric boundary layer has been successfully inverted,and the obtained height has obvious diurnal variation characteristics and is consistent with the diurnal variation trend of environmental temperature.The successful inversion of atmospheric boundary layer height using SLidar system through two experiments shows that the SLidar system is effective in detecting boundary layer aerosols,and SLidar system is greatly effective in environmental pollution monitoring.