Modern Day Re-analysis of Pinatubo SO2 Injection, Cloud dispersion and Stratospheric Aerosols
Abstract
Cataclysmic June 15 1991 eruption of Mt. Pinatubo injected largest amount of SO2 in the lower stratosphere during the satellite era. The resulting volcanic clouds were tracked by the NASA's Nimbus 7 TOMS sensor that provided first estimates of total emissions of SO2 gas ( 15+/-3 Mt). Over time SO2 converted to long-lasting sulfate aerosols affecting radiation balance and composition of the stratosphere. Large numbers of articles and papers published in the past 25 years make this the most well-studied volcanic eruption. Still, several unresolved scientific issues remain: SO2 injection height, subsequent lofting of SO2 and aerosols in the stratosphere, how much sulfate aerosols were produced in the eruption (i.e., initial sulfate to SO2 ratio), and impact on stratospheric ozone. To answer these questions we have re-analyzed past satellite measurements using modern day tools, such as re-analyzed wind data from Goddard Modeling and Assimilation Office (GMAO), improved trajectory analysis tools, better radiative transfer model to process backscatter UV data from N7/TOMS and two NOAA SBUV/2s sensors, which provided measurements at shorter UV wavelengths that are sensitive to aerosols and SO2 in the mid stratosphere ( 25 km). We have also re-analyzed aerosol data from SAGE, AVHRR, and several instruments on the UARS satellite. These data provide strong support for recent assessment by modelers that the bulk of SO2 mass injected by the volcano was well below the 25 km altitude, contrary to earlier estimates. We also find convincing evidence that there was significant amount of sulfate aerosols embedded even in the day-old SO2 cloud. These results strongly support the hypothesis that SO2 gas self-lofted to 25 km as seeen by UARS MLS several weeks after the eruption and aerosols to 35 km, as seen by the SAGE sensor several months later.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.V32A..03B
- Keywords:
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- 1616 Climate variability;
- GLOBAL CHANGEDE: 8408 Volcano/climate interactions;
- VOLCANOLOGYDE: 8428 Explosive volcanism;
- VOLCANOLOGYDE: 8488 Volcanic hazards and risks;
- VOLCANOLOGY