Effects of the El Chichón Volcanic Cloud on Solar Radiation Received at Fairbanks, Alaska

Abstract

Detailed insulation measurements have been carried out in Fairbanks for the last four years. Beginning on 15 November 1982, these measurements showed substantial changes, believed to be due to the dust cloud of El Chichón. The volcano, situated in Mexico, erupted most intensely on 4 April 1982, putting a large amount of material into the atmosphere. The long travelling time to the North is in line with results found by Rao and Bradley (1983). Compared to clear-day data for previous years, clear days for the time period 15 November 1982?31 May 1983 showed a decrease in the direct beam of24.8%, an increase in the ratio of diffuse to global radiation of 76%, and a decrease in the global radiation of about 5%. A decrease in the direct beam, a substantial increase in the diffuse radiation, and a small decrease in the global radiation are typical for increased turbidity of the atmosphere, but the volcanic cloud caused changes greater than those due to "normal" turbidity changes.