File:Two Views of Fires in the Southeastern United States (MODIS 2024-12-05).jpg

English: Aqua Overpass Terra Overpass

Streamers of smoke streaked the skies over the Southern United States on December 3, 2024. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired a true-color image of active fires accompanied by smoke plumes on that same afternoon. In contrast, when the MODIS instrument on the Terra satellite acquired a true-color image in its morning pass, no smoke was visible. The views can be compared simply by clicking on the titles below the images.

The plumes seen on the Aqua image are consistent with multiple small fires actively burning across the region. In the morning, when winds were not active, no plumes were visible. So, the two views give a distinctly different impression of fire across the region. Not surprisingly, the Aqua view, with the plumes visible, gives a more accurate depiction of the situation. Using the NASA Worldview App to add the data from MODIS thermal bands to both the Aqua and Terra images reveals red “hot spots” that confirm fire activity at each of the afternoon (Aqua) plumes. The hotspots were also present in the morning (Terra) image, despite the lack of smoke.

When MODIS true-color images are combined with data from the instrument’s thermal bands, MODIS is a highly accurate, sensitive, and widely used tool for fire detection. However, when the thermal bands are not used, as in these images, the detection of fire becomes more difficult.

The widespread nature of these fires and time of year strongly suggests that most of them are prescribed burns. Prescribed burns are fires that have been deliberately ignited and controlled by trained personnel, typically to ensure ecosystem health and reduce the risk of large, destructive wildfires.