40th anniversary of the Mount St. Helens eruptionNOAA GOES-3 Visible (0.65 µm) images at 1545 and 1615 UTC (above) showed the volcanic cloud shortly after the explosive eruption of Mount St. Helens on 18 May 1980. GOES-3 was decommissioned in 2016.
The corresponding GOES-3 Infrared (11.5 µm) image at 1545 UTC (below) appeared to display a small “enhanced-V” or cold/warm (-65ºC/-47ºC) thermal couplet signature downwind (east) of the volcanic cloud’s overshooting top.A comparison of GOES-3 Visible and Infrared images (below) showed that a large portion of the volcanic cloud exhibited IR brightness temperatures of -60ºC or colder (darker red color enhancement) as the feature moved rapidly eastward during the first 10 hours following the eruption. The volcanic cloud was also captured on NASA SMS-2 Visible (0.62 µm) and Infrared (11.6 µm) imagery (below). An animation that cycles through both SMS-2 Visible and Infrared images can be seen here. SMS-2 “Visible/Infrared Sandwich” Red-Green-Blue (RGB) images are shown below. Archived GOES-3 and SMS-2 imagery was provided by SSEC Satellite Data Services.
The monitoring of volcanicashplumes and their attributes have greatly increased from 1980 to today. Moving from qualitative (somewhat after the fact imagery) to quantitative applications (that are much more timely)! Due to the large number of volcanoes, coupled with the increase in satellite observations, satellite observations are key in monitoring the world’s volcanoes for aviation safety and other uses. More on volcanic ash monitoring.