Precise detection of near ground aerosol extinction coefficient profile based on CCD and backscattering lidar

Atmospheric aerosol, a main pollutant source, mainly exists in planetary boundary layer, and the precise detection of its vertical distribution, especially in the near ground, has an important application value. Backscattering lidar is a powerful tool for aerosol extinction coefficient profile detection, but no signals or only weak signals could be received in near distance because of the blind zones and transition regions. The above problems were resolved by combining CCD detection with backscattering lidar, and the aerosol extinction to backscattering coefficient (lidar ratio) was retrieved accurately with the combined measurement of Raman scattering channel. In order to validate CCD detection, two different CCD lidars with different CCD position distance and focal length were designed respectively for comparison. The relative difference of aerosol extinction coefficients from two CCD lidars was less than 3% under about 1.2 km height, which indicates that the detection results are in good agreement. Case study shows that aerosol extinction coefficient near the ground is inhomogeneous with height, and sometimes increases with time and sometimes decreases.