Stratospheric aerosol monitoring with lidar. Conventional backscatter versus raman lidar observations of Pinatubo aerosol

Long-term observations of the stratospheric aerosol layer after the Pinatubo eruption conducted with a conventional backscatter lidar at Garmisch-Partenkirchen (47.5 deg N, 11. 1 deg E) and a recently developed Raman lidar at Geesthacht (53.40 N, 10.4 deg E) are compared. The theoretical background of the fundamentally different lidar techniques is described, and advantages and shortcomings of the different methods are briefly discussed. The good agreement between the two data sets in terms of particle optical depth and mass and surface-area concentrations confirms the reliability of conventional-lidar observations after a major volcanic eruption and demonstrates the usefulness of the Raman-lidar technique for stratospheric aerosol studies. The latter technique allows the derivation of the relevant optical and physical aerosol parameters without applying a sophisticated aerosol model as is necessary in the case of the evaluation of conventional-lidar signal profiles.