| At present,China is facing the issue of climate change,and part of the reason of climate change is the existence of the aerosols.Because of the complex physical properties of the aerosols,it can affect the climate change by scattering and absorbing sun radiation.In addition,aerosols can also be used as the condensation nucleus of clouds to affect the formation and disappearance of clouds,to affect climate change.Therefore,it is of great significance to study the physical properties of aerosol.As an active optical remote sensing device,Lidar receives the backscattered light of atmospheric molecules and aerosols through the physical interaction between laser and atmospheric particles,which has incomparable advantages in detecting the optical properties,depolarization properties,microphysical properties and distribution characteristics of aerosols.In order to improve the measuring accuracy of aerosol lidar in detecting aerosol optical property parameters,this paper mainly relies on the standard aerosol lidar and networked lidar of the China Meteorological Administration Meteorological Observation Center to carry out research on the calibration technology of lidar,including the calibration of optical system and electronic system,and is verified by lidar self-calibration experiment and comparison calibration experiment.The data quality and consistency of aerosol optical parameters are greatly improved.Then,aiming at the problem that the lidar system itself does not have a Raman receiving channel,so the lidar ratio inversion cannot be carried out,this paper used a lidar-Sun photometer joint inversion algorithm to obtain an average lidar ratio of 34±3 sr for dust weather processes and 75±7 sr for haze weather processes,improving the inversion accuracy of aerosol optical properties.By establishing a simulation model,selecting case data and continuous data,and verifying and analyzing the gradient method,normalized gradient method,and wavelet covariance transform method,the stability of the wavelet covariance transform method for determining the boundary layer height is much higher than two other methods.Using the inverse distance weighting interpolation method,the "puzzle" of networked lidar observation data was realized,and a twodimensional distribution plane of aerosol optical characteristics was obtained,and obtain the transport mechanism of dust in Beijing is mainly northwest-central region-southeast-northeast region.Finally,the aerosol optical properties during the pollution process were analyzed by using the network lidar observations and multi-source data.It is found that the extinction coefficient in the atmospheric boundary layer of Beijing during the Winter Olympics is high in the southeast and low in the northwest.Under adverse diffusion conditions,in addition to the accumulation of local emissions causing aerosol pollution in Beijing,the main of aerosol pollution in Beijing can be mainly divided into two aspects: one is the transportation of dust aerosol particles to Beijing from northwest Mongolia,Inner Mongolia and other places;the other is the transportation of man-made aerosol particles from Hebei,Tianjin and other surrounding cities to Beijing.Therefore,the control of air quality should not only focus on local energy conservation and emission reduction,but also pay attention to the transportation of regional air pollutants. |
