Influence of the Pinatubo eruption on the aerosol optical depth in the Arctic in the summer of 1993

In the summer of 1993, measurements of the spatial distribution of atmospheric optical aerosol thickness were conducted in the region of the Laptev Sea, the Kara Sea and the Taimyr peninsula, using an aircraft visible and UV band spectrophotometer. The Arctic atmosphereʹs aerosol optical depth was measured using I1-18 ‘Cyclone’ aircraft-meteolab as a platform at an altitude ranges of 100–8500 m. It was observed that the troposphere aerosol was concentrated in the altitude range 100–4000 m. The light extinction of the troposphere column was approximately 0.05 for a wavelength of 400 nm. A comparison with the results of measurements made in the same region in March-April 1990 shows a decrease of more than 3–5 times in troposphere aerosol optical depth in the Arctic during summer months. It was also found that there was a relatively clean area above 4000 m in this season in the Arctic troposphere. In addition, an increase in aerosol optical thickness in the stratosphere is observed. The value of aerosol optical depth measured from the level 8200 m was 0.1 for a wavelength of 500 nm. The spectral dependence of the stratospheric optical thickness has a complicated form with at least two local maxima. Estimates of the size and concentration of stratospheric aerosol particles are in agreement with in-situ measurements after the Mount Pinatubo eruption.