The Stratospheric Impact of the Eruption of Pinatubo

The eruptions of the Philippine volcano Pinatubo (15.14°N, 120.35°W) in June 1991 caused the largest impact to stratospheric aerosols experienced probably in this century. Early estimates place the SO2 injected to altitudes of at least 30 km at 2 or more times that from the 1982 eruptions of El Chichon. El Chichon put about 6 megatonnes of SO2, or 12 megatonnes of sulfuric acid aerosol, into the lower-to-middle stratosphere making it the largest in the Northern Hemisphere for at least 50 years. An eruption of the magnitude of Pinatubo is important for studies of global change. In particular, its effects to cooling the Earth's surface and possibly masking greenhouse warming must be understood. The heterogeneous chemical effects of this new surface area and the potential for ozone reduction must also be studied. Other potential impacts include the possibility of increased cirrus cloud production and effects of this volcanic layer on producing artifacts in various ground-based and satellite-based remote sensor retrievals. Another effect clearly observed after El Chichon, was the serious crazing of acrylic windows on aircraft flying in polar regions and, therefore, at stratospheric altitudes where aircraft came into contact with the increased sulfuric acid aerosol produced by the El Chichon eruption.