On September 23, 1997 many hot spots were apparent on the 4 micron image from GOES-8. Since the 11 micron window channel does not display an elevated signal at these locations, the 4 micron hot spots are probably due to sub-pixel burning. Hot spots have been observed in Virginia on more than one occasion this summer. However, there seems to be more activity in today's image. A comparison with an image from the same time on September 22, 1997 will reveal that the hot spots are not in the same location, indicating that they are probably the result of agricultural burning or wildfires.
At 16:45 UTC, the time the fires were observed in the 4 micron image, cloud cover may be obscuring the detection of plumes in the Virginia area. The plumes which are visible have been marked on the visible imagery animation. The plume at location A provides the strongest signal of all the plumes. However, no hot spot appears in that location on the 4 micron image. This plume may be from a smoldering fire. Inefficient, low temperature, smoldering fires can produce substaintial emissions without producing an elevated signal in the 4 micron imagery.
