Spectral solar irradiance in northern Scandinavia before and after Pinatubo

Z. D. ADEYEFA, B. HOLMGREN, J. A. ADEDOKUN

Abstract

Spectral and broad-band solar radiation measurements were made non-continuously between 1990 and 1994 at Abisko (68º 21' N, 18º 49' E), which is about 200 km north of the Arctic Circle in northern Sweden. The increase in the atmospheric turbidity due to the huge amounts of volcanic aerosols which were injected into the stratosphere by the volcanic eruptions of Mount Pinatubo in June 1991 consequently led to a decrease in the direct irradiance which is considerable especially in the visible region, varying between 18% and 30% at solar elevations of 40º and 15º respectively. Although less than the direct irradiance due to the concomitant increase in the diffuse radiation, the change in the total radiation was also significant (about 1.4 and 8 at solar elevation angles of 40º and 15º respectively).

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