Typical vertical profiles of aerosol spectral extinction coefficients derived from observations of direct solar radiation extinction during the aircraft experiments Arctic Haze 94/95 and Merisec 93/94

This paper presents first of all the method of observation of vertical profiles of aerosol spectral optical thickness and aerosol spectral extinction coefficients, taken during four campaigns as part of the German-Russian aircraft project ‘Arctic Haze/Merisec’ in the years 1993, 1994 and 1995. These measurements reported here are concentrated on an episode on 5 April 1994 in the so-called ‘Laptev Sea’ box over a latitude range from 82°–86°N and 197°-117°E, within a horizontal length of approximately 200 km, a width of nearly 40 km and a height up to the tropopause at about 8 km. Optical thickness and extinction values are presented for 6 heights within the troposphere, at 8 wavelengths varying from 0.4 up to 1.04 μm. Aerosol extinction coefficients are found to be in favourable agreement with those obtained from inferred values using optical aerosol particle data. ce of aerosol optical thickness of similar order of magnitude to near the ground level values has been found for aerosol layers some 100ʹs m below the tropopause.