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Measurements of SO2 in the Mount St. Helens debrisRoutine measurements of ozone and SO2 are made with the Dobson and Brewer spectrophotometers at the Atmospheric Environment Service in Downsview Ontario. On May 20 and 21, 1980, large values of column SO2 were observed with both spectrophotometers at the time of passage of the Mount St. Helens debris. Enhanced SO2 values were first observed at 1800Z on May 20. The maximum column amount of SO2 measured was 0.06 cm at 2200 Z. On May 21, SO2 values slowly decreased from 0.03 cm at 1100 Z cm to 0.01 cm at 2000Z. Typical SO2 amounts due to pollution at the Downsview site are approximately 0.003 to 0.005 cm. At the same time of maximum SO2 enhancement, both Dobson and Brewer spectrophotometers measured a 0.040 cm decrease of total ozone. It is not clear whether the decrease of total ozone was caused by the volcanic cloud or natural ozone variability. Air mass trajectories indicate that the altitude of the debris cloud, which passed over Downsview at the time, was between 10 km and 12 km.
Document ID
19830003283
Document Type
Conference Paper
Authors
Kerr, J. B. (Atmospheric Environment Service Downsview Ontario, Canada)
Evans, F. J. (Atmospheric Environment Service Downsview Ontario, Canada)
Mateer, C. L. (Atmospheric Environment Service Downsview Ontario, Canada)
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
ENVIRONMENT POLLUTION
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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