National Aeronautics and Space Administration

Abstract. The mass of SO2 emitted by the 16 major exploisve eruptions of Redoubt Volcano between December 1989 and April 1990 have been examined by the Total Ozone Mapping Spectrometer (TOMS) carried on the Nimbus 7 satellite. Because of low light levels during the winter months, TOMS could not detect SO2 at high northern latitudes. Thus, the major eruptions from December through February could not be monitored unless winds brought the clouds to latitudes lower than about 58N. Only two SO2 clouds were observed in the satellite data - an approximatley 100-kiloton (kt) cloud on December 16 over Nevada and eastern California, and a 10-kt cloud on March 9 directly over the volcano. We speculate that the major eruption on December 15 at 1015 hour produced the 100-kt cloud seen on December 16, and the mass of SO2 injected into the atmosphere at that time was 175 +/- 50 kt.