SATELLITE MEASUREMENT OF SULFUR-DIOXIDE FROM THE REDOUBT ERUPTIONS OF1989-1990

The mass of SO2 emitted by the 16 major explosive eruptions of Redoubt Volcano between December 1989 and April 1990 have been examined by th e Total Ozone Mapping Spectrometer (TOMS) carried on the Nimbus 7 sate llite. Because of low light levels during the winter months, TOMS coul d not detect SO2 at high northern latitudes. Thus, the major eruptions from December through February could not be monitored unless winds br ought the clouds to latitudes lower than about 58 degrees N. Only two SO2 clouds were observed in the satellite data - an approximately 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 t hat 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 atmo sphere at that time was 175+/-50 kt.