Research On Planetary Boundary Layer Height And Characteristics Based On Atmospheric Remote Sensing Lidar

In recent years,the trouble of atmospheric pollution has grown increasingly prominent.As the layer that interacts most closely with the surface,the atmospheric boundary layer has an important impact on human health,transportation and environmental pollution.The planetary boundary layer height(PBLH)determines the diffusion of pollutants and is also an important parameter in various climate models.Lidar,as a device for active remote sensing of atmospheric aerosols,possesses the virtues of all-day detection and high spatial-temporal resolution.It is widely used in fields such as atmospheric detection and environmental monitoring.However,because the lidar needs to meet the requirement of reaching a certain detection distance,there are often large blind areas and transition areas,resulting in inaccurate boundary layer echo signals.Without correcting the signal,the lidar data cannot be used to determine the PBLH.In addition,the structure of the atmosphere is complex and diverse,and there are often suspended aerosol layers and clouds above the boundary layer,which has an important impact on the correct inversion of the PBLH.Based on the above problems,this article starts from the detection of atmospheric aerosols by lidar and establishes the systematic research content of inversion of PBLH to improve the accuracy of lidar detection at PBLH.The main research contents include:1.Proposed a new technique of maximum limited height initialization and range restriction(MLHI-RR).Owing to the effect of the suspended aerosol layer and cloud layer above the boundary layer,commonly used lidar methods to retrieve the PBLH often mistakenly judge the boundary of the lofted aerosol layer or cloud layer as the height of the atmospheric boundary layer,which brings challenges to the accurate acquisition of PBLH.The MLHI-RR technology limits the lidar data in a certain height range,ensuring that the boundary layer top is within this range,while the suspended aerosol layer and the cloud layer are excluded to eliminate the influence of multiple aerosol layers.2.Improved the algorithm for detecting the PBLH based on the CALIOP data.Compared with ground-based lidar,CALIOP has unique advantages in space coverage.This paper combines wavelet covariance transform method and standard deviation method to develop the algorithms suitable for inversion of PBLH based on CALIOP data,which considers the factors that affect the PBLH under different atmospheric conditions and removes the suspended aerosol layer,cloud layer as well as underlying surface.3.Analyzed the characteristics of the PBLH in Hangzhou urban area in 2019.Based on the research above,a visualization software based on Micro Pulse Lidar was developed to retrieve the PBLH,which greatly saved the time of data processing.And the PBLH retrieved by the software is used to analyze the characteristics of the PBLH in Hangzhou urban area in 2019.A series of PBLH inversion techniques and methods studied in this paper can effectively improve the accuracy of the determination of PBLH,which is of great significance for lidar to detect atmospheric aerosols and atmospheric boundary layer and provides valuable data support for the governance and supervision of air pollution.