Trajectories of the Mount St. Helens eruption plume
The plume of the major eruption of Mount St. Helens on 18 May 1980 penetrated 10 to 11 kilometers into the stratosphere, attaining heights of 22 to 23 kilometers. Wind shears rapidly converted the plume from expanding vertical cone to a thin, slightly inclined lamina. The lamina was extruded zonally in the stratosphere as the lower part moved eastward at jet stream velocities, while the upper part slowly moved westward in the region of nonsteady transition from the westerlies to the summer stratospheric easterlies. Trajectories computed to position the NASA U-2 aircraft for sampling in the plume are described. Plume volume after 8 hours of strong volcanic emission is estimated at 2 x 10/sup +6/ cubic kilometers. Only about 1 percent of this volume is attributed to the volcano; the rest was entrained from the environment.
- OSTI ID:
- 6543829
- Journal Information:
- Science (Washington, D.C.); (United States), Vol. 211
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SULFUR DIOXIDE
ENVIRONMENTAL TRANSPORT
AIR POLLUTION
MT ST HELENS
PLUMES
STRATOSPHERE
WIND
CASCADE MOUNTAINS
CHALCOGENIDES
EARTH ATMOSPHERE
FEDERAL REGION X
MASS TRANSFER
MOUNTAINS
NORTH AMERICA
OXIDES
OXYGEN COMPOUNDS
POLLUTION
SULFUR COMPOUNDS
SULFUR OXIDES
USA
WASHINGTON
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)