| Based on the multi-wavelength Raman polarization lidar independently developed by Lanzhou University,combined with sun photometer and sounding balloon observation,this study explored the vertical distribution characteristics of microphysical properties of dust in the hinterland of Taklimakan Desert——Tazhong Station.Based on the multi-wavelength characteristics of multi-wavelength lidar,a set of calculation methods of planetary boundary layer height（PBLH）based on the multi-wavelength lidar is developed and compared with the PBLH products of reanalysis data MERRA-2.The correlation between dust optical thickness（DOD）and PBLH,as well as the interaction between dust and clouds,was discussed.By utilizing the long time series characteristics of reanalysis data,the impact of meteorological factors on the changes in DOD time series in the Tazhong region was explored,providing theoretical and empirical support for future lidar networking and long-term monitoring,and providing theoretical and data support for the wider application of multi-wavelength Raman lidar in atmospheric detection and assimilation of climate models.Firstly,using various satellite data such as cloud aerosol lidar and infrared path observation satellite（CALIPSO）,ozone layer monitor（OMI）and Moderate-Resolution Imaging Spectroradiometer（MODIS）,the spatial distribution characteristics of dust microphysical properties in the Tazhong station were discussed,so as to have a background understanding of the distribution of dust optical properties（DOD）in the Tazhong station and its surrounding areas.The results indicate that the aerosol optical thickness（AOD）at a wavelength of 550 nm in the Tazhong area is higher than that in the surrounding area,and the?ngstr?m exponent（AE）at 412–470 nm is lower than that in the surrounding area,indicating that the Tazhong area is mainly composed of particles with higher concentrations and coarser particle sizes.According to the three-dimensional spatial distribution of DOD in the long time series of AOD,the aerosols in the Tazhong area are mainly composed of dust aerosols,with DOD accounting for more than 85%of the AOD in Tazhong station below 10 km in vertical distribution.This proves the rationality of assuming that the aerosols in Tazhong station are mainly pure dust or pure pust and polluted dust,without considering other types of dust when using multi-wavelength Raman polarization lidar to detect the microphysical characteristics of dust in Tazhong station.Then,based on the ground remote sensing instrument——multi-wavelength Raman polarization lidar,a set of algorithms suitable for the lidar system was developed.The algorithm was applied to encrypted experimental observations from July 3 to July31,2019,and the vertical distribution of microphysical properties of dust aerosols was inverted.The optical characteristics of dust aerosols in northwest China were revealed,and the optical and microphysical parameter datasets of dust aerosols in northwest China were obtained.Based on the MERRA-2 reanalysis data and multi-wavelength Raman polarization lidar observation data,the interaction between DOD and PBLH in the Tazhong station,as well as the interaction between dust and clouds,was discussed in a long-term series.A multiple linear regression model was established to quantify the contribution of meteorological factors to DOD changes.The results indicate that:（1）The dust aerosol in Tazhong station can rise to 6 km in summer,with a mass concentration of 400–1000μg cm-3,and most of the dust remains within 2 km.In addition,the height of the boundary layer can reach 5–6 km in the afternoon.The particle depolarization ratio（PDR）of dust in the Tazhong station is 0.32±0.06 and 0.27±0.04 at 532 nm and 355 nm,respectively.The dust lidar ratio（LR）in the Tazhong station is 49±19sr at 532 nm and 43±12 sr at 355 nm,providing a reference for the hypothesis of LR in the experimental observation of the mie-scattering lidar in the area.（2）A new method for calculating PBLH has been developed using this multi-wavelength lidar system.Using MERRA-2 data from 1980 to 2021,a correlation analysis was conducted between PBLH products and DOD time series.It was found that the Pearson correlation between the two reached 0.77,providing more possibilities for discussing changes in PBLH and DOD.（3）The absorption coefficient of dust in the Tazhong station obtained by sun photometer and multi-wavelength Raman lidar is smaller than that of anthropogenic dust over East Asia and Central Asia,and the single scattering albedo is higher than that obtained by MODIS.The vertical distribution and column distribution characteristics of microphysical properties of dust were used as inputs to the SBDART model,and it was found that the difference in atmospheric bottom and aerosol radiative forcing caused by the two input methods was over 95%,emphasizing the importance of vertical observation of dust characteristics in obtaining more accurate radiative forcing.（4）The correlation between ice condensation nodules and wind speed,cloud condensation nodules and relative humidity in D10 mode was discussed to provide data support for assimilation of meteorological elements into climate models.Multi-wavelength Raman Lidar was used to observe the interaction between aerosol and cloud.The results show that cloud particle number concentration,effective particle number and liquid water content increase exponentially with the increase of dust extinction coefficient.（5）The relative contribution resolution of DOD in the Tazhong station influenced by meteorological factors is as follows:surface wind speed contributes the most,accounting for 44%,followed by 500 h Pa temperature,accounting for 14%,surface temperature is 11%,normalized vegetation index（NDVI）accounts for 10%,500 h Pa wind speed accounts for 9%,and other factors account for relatively small proportions.Thermal and dynamic factors are the main influencing factors of DOD change,followed by vegetation cover,highlighting the interrelationship between climate and environment change under bare surface in the dust source area.The inversion method can be widely applied to the generation of dust microphysical properties products in multi-wavelength Raman Lidar,which accumulates relevant experience for the discussion of the interaction between dust and cloud microphysical and meteorological elements. |
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