The German Aerosol Lidar Network: Methodology, Data, Analysis

The German Aerosol Lidar Network has attempted, for the first time worldwide, to establish a cli- matological data set for the aerosol vertical distribution over several stations in a quantitative and coordinated approach. Quantitative results have been obtained by employing advanced lidar methods like Raman or scanning lidar to retrieve profiles of the extinction coefficient directly. To provide for a sufficiently homogeneous data set substantial effort was put into data quality assurance. Intercom- parisons were performed at both system and retrieval algorithm levels. A very satisfactory agreement between the different systems was achieved. A rather large data set of aerosol extinction and backscat- ter profiles was collected using regularly scheduled measurements on predetermined days and times to avoid a bias due to ”preferred” weather conditions for lidar observations. A large number of ad- ditional measurements were devoted to studies of special weather conditions. The results of special studies related to the aerosol distribution associated with high pressure systems and cold front pas- sages are reported as well as special studies on the long term development of the stratospheric aerosol distribution, transport processes in an Alpine valley, and long range transport of aerosol. The retrieval of aerosol microphysical properties using lidar measurements at several wavelengths is described mathematically and applied to actual examples, showing very promising results. Several methods for the statistical analysis of the climatological data set are developed making use of the simultaneously collected data set of backtrajectories. Products of these analyses include the seasonal dependence of boundary layer heights, the mean extinction and backscatter profiles, the mean optical depth, sep- arately for PBL and free troposphere, the seasonal dependence of aerosol extinction, the statistical distribution of aerosol extinction and of extinction-to-backscatter ratio values, and the dependence of aerosol optical properties on the airmass history

The German Aerosol Lidar Network: Methodology, Data, Analysis, MPI-Report 317

The German Aerosol Lidar Network has attempted, for the first time worldwide, to establish a cli- matological data set for the aerosol vertical distribution over several stations in a quantitative and coordinated approach. Quantitative results have been obtained by employing advanced lidar methods like Raman or scanning lidar to retrieve profiles of the extinction coefficient directly. To provide for a sufficiently homogeneous data set substantial effort was put into data quality assurance. Intercom- parisons were performed at both system and retrieval algorithm levels. A very satisfactory agreement between the different systems was achieved. A rather large data set of aerosol extinction and backscat- ter profiles was collected using regularly scheduled measurements on predetermined days and times to avoid a bias due to ”preferred” weather conditions for lidar observations. A large number of ad- ditional measurements were devoted to studies of special weather conditions. The results of special studies related to the aerosol distribution associated with high pressure systems and cold front pas- sages are reported as well as special studies on the long term development of the stratospheric aerosol distribution, transport processes in an Alpine valley, and long range transport of aerosol. The retrieval of aerosol microphysical properties using lidar measurements at several wavelengths is described mathematically and applied to actual examples, showing very promising results. Several methods for the statistical analysis of the climatological data set are developed making use of the simultaneously collected data set of backtrajectories. Products of these analyses include the seasonal dependence of boundary layer heights, the mean extinction and backscatter profiles, the mean optical depth, sep- arately for PBL and free troposphere, the seasonal dependence of aerosol extinction, the statistical distribution of aerosol extinction and of extinction-to-backscatter ratio values, and the dependence of aerosol optical properties on the airmass history