The NASA/Ames Research C-141 aircraft underflew the Mount St. Helens ejecta plume in Utah three days after the eruption. Upward-looking 20–40-μm on-board radiometry provided data resulting in a calculated long-wave transmission of 0.93. From this value, an optical depth of 0.073 is inferred. This value is compared with an accepted background, stratospheric infrared optical depth of 0.06. Assumptions on particle size, shortwave albedo, and thermal warming imply little surface temperature change caused by the ejecta on the third day immediately following the eruption.
© 1981 Optical Society of America
Original Manuscript: September 25, 1980
Published: January 1, 1981
P. M. Kuhn, L. C. Haughney, and R. C. Innis, "Long-wave stratospheric transmission of Mount St. Helens ejecta," Opt. Lett. 6, 24-26 (1981)