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Simulation studies of the physical and chemical processes occurring in the stratospheric clouds of the Mount St. Helens eruptions of May and June 1980The large and diverse set of observational data collected in the high-altitude clouds of May 18, May 25, and June 13, 1980 was organized and analyzed for trends which reveal the processes at work. The data were used to guide and constrain model simulations of the volcanic eruptions. A comprehensive one-dimensional model of stratospheric sulfate aerosols, sulfur precursor gases, and volcanic ash and dust particles is utilized which accounts for homogeneous and heterogeneous chemistry in the clouds, aerosol nucleation and growth, and cloud expansion. Computational results are given for the time histories of the gaseous species concentrations, sulfate aerosol size dispersions, and ash burdens in the eruption clouds. The long-term buildup of stratospheric aerosols in the Northern Hemisphere and the persistent effects of injected chlorine and water vapor on ozone are discussed. It is concluded that SO2, water vapor, and ash are the most important substances injected by the volcano into the stratosphere, with respect to both the widespread effects on composition and the impact on climate. It is found that the volcano probably had little influence on the climate ( 0.05 K global surface cooling) or on stratospheric ozone ( 0.2 percent maximum hemispherical reduction).
Document ID
Document Type
Conference Paper
Turco, R. P. (R and D Associates Moffett Field, CA, United States)
Toon, O. B. (NASA Ames Research Center Moffett Field, CA, United States)
Whitten, C. (NASA Ames Research Center Moffett Field, CA, United States)
Keesee, R. G. (NASA Ames Research Center)
Hamill, P. (Systems and Applied Sciences Corp.)
Date Acquired
August 11, 2013
Publication Date
October 1, 1982
Publication Information
Publication: NASA. Langley Research Center Atmospheric Effects and Potential Climatic Impact of the 1980 Eruptions of Mt. St. Helens
Subject Category
Funding Number(s)
Distribution Limits
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19830003264Analytic PrimaryAtmospheric Effects and Potential Climatic Impact of the 1980 Eruptions of Mount St. Helens
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