The data from airborne lidar sounding of lower stratosphere aerosol in the Arctic up to 23 km carried our on 3-5 February, 1988 are reported. The measurements on the optical characteristics of the atmosphere have revealed the presence of aerosol layers at an altitude of 21-23 km. These strata referred to as polar stratospheric clouds have scattering and depolarization coefficients of 10-3-10-4m-1 and 0.3-0.4 respectively. Satellite images, aircraft in-flight data, and balloonborne observations show this kind of clouds tends to occur at temperatures below -70° and makes a substantial contribution to the ozone layer depletion.