AbstractA LIDAR instrument is operated at Ny‐Ålesund, Spitsbergen (79N, 12E). Backscatter profiles of stratospheric aerosols like polar stratospheric clouds (PSCs) are determined at a wavelength of 353 nm. PSC data are shown for January 1989 and 1990. The data are correlated with atmospheric temperature. In August 1991 an aerosol layer was found, which presumably originates from the volcanic eruption of Mount Pinatubo. The modification of the LIDAR instrument for the European Arctic Stratospheric Ozone Expedition (EASOE) in the winter 1991/92 is presented.