Pinatubo eruption effects on solar radiation at Almeria (36.83°N, 2.41°W)

Abstract

Volcanic eruptions are responsible for the injection of SO² into the stratosphere, and the subsequent production of stratospheric aerosol layer. In June 1991, Mount Pinatubo injected approximately 20 millions metric tons of SO₂ into the stratosphere. The volcanic aerosol circled the earth in 21 days, covering an area of about 42% of the earth’s surface. A few weeks after the Mount Pinatubo eruption, an abrupt change was detected on the solar radiation flux measurements registered in our radiometric station, located at a sea shore location (36.83°N, 2.41°W, 10 m a.s.l). The Mann-Kendall rank statistic confirms this abrupt change with a high confidence level. We have evaluated the quantitative effect over different terms of solar radiation flux. There is a significant reduction in direct solar radiation of about 10%, while global solar irradiance shows a reduction of about 4%, due to the compensation effect of increasing diffuse irradiance. As in similar analyses carried out in mid-latitude locations, we found a decay of the aerosol effects during the 1992 summer and an enhancement in late 1992.