AbstractThe background aerosol conditions and the conditions contaminated with aerosol of antropogenic origin (Arctichaze) were investigated during two Arctic campaigns, the Arctic Study of Tropospheric Aerosols, Clouds andRadiation (ASTAR) in 2004 and Svalbard Experiment (SVALEX) in 2005, respectively. Results obtained byapplication of the two-stream inversion algorithm to the elastic lidar signals measured on two days representativefor each campaign are presented. The calculations were done using signals obtained by the nadir-looking AirborneMobile Aerosol Lidar (AMALi) probing lower troposphere from the AWI research aircraft Polar 2 overflying thestationary Koldewey Aerosol Raman Lidar (KARL) based at the AWI Koldewey Research Station in NyÅlesund, Svalbard. The method allowed independent retrieval of extinction and backscatter coefficientprofiles and lidar ratio profiles for each of the two days representative for both clean and polluted lowertroposphere in Arctic.