CALIBRATION OF THE LIDAR MEASUREMENT OF TROPOSPHERIC AEROSOL EXTINCTION COEFFICIENTS

In the derivation of the vertical profile of tropospheric aerosols from lidar data, one has to assume an appropriate value for the aerosol extinction coefficient at a reference point, a few kilometers or more above the ground. If the aerosol contribution at this point is not negligible compared to the molecular contribution, the resulting aerosol extinction through the atmosphere is affected by this boundary value. Here we propose the use of a ground-level extinction coefficient measured by an integrating nephelometer for the calibration of lidar data. In order to connect the ground value to the overlap point of a vertical lidar, additional data are provided from slant path observation using a portable lidar.