Effects of the El Chichon volcanic dust cloud on insolation measurements at Corvallis, Oregon (U.S.A.)

Abstract

Insolation measurements made on clear days at Corvallis, Oregon, since the last week of November, 1982, have indicated a decrease of about 14% in the atmospheric clearness index, an increase by a factor of about 2.3 in the ratio of the diffuse sky irradiation to the global irradiation and a decrease of about 28% in the transmittance of the atmosphere for the direct normal solar irradiation compared to the normal, clear‐day values. It is felt these anomalies are caused by the increased atmospheric turbidity due to the El Chichon volcanic dust cloud.