Temperature and ozone anomalies as indicators of volcanic soot in the stratosphere
V.V. Zuev, N.E. Zueva, E.S. Saveljeva
Institute of Monitoring of Climatic and Ecological Systems of the Siberian Branch of the Russian Academy of Sciences, 634055, Tomsk, 10/3, Academichesky ave
Keywords: vertical temperature profiles, vertical profiles of ozone, eruption of Mount Pinatubo, stratospheric volcanogenic aerosol, soot
Abstract
The role of volcanogenic aerosols in the formation of ozone and temperature anomalies in the tropical stratosphere registered after the eruption of Mount Pinatubo in June 1991 is analyzed in the paper by the 30-year period of balloon measurements at Hilo station in Hawaii. Positive temperature deviations and negative ozone deviations in vertical profiles of greater than or equal to 2σ from perennial average are considered as anomalies. The stratospheric anomalies observed in the second half of 1991 agree well with the presence of volcanic ash, remained in the stratosphere for about six months. However, temperature anomalies and stratospheric ozone depression, observed subsequently during 2-3 years, cannot be explained by long-lived sulfuric acid aerosol. The formation mechanism in the stratosphere of long-lived volcanic soot formed by thermal decomposition of methane in the eruption column, intensively absorbing solar radiation and destroying ozone on its surface is suggested in the article. The largest ozone anomaly observed in the lower stratosphere during the second half of 1992 is explained by the calculated deposition rate of soot subject to high efficiency of ozone depletion on its surface.
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