GOES-16 daytime and nighttime images of the West Mims Fire in Georgia
** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **A daytime comparison of GOES-16 ABI “Blue” Visible (0.47 µm), “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above; also available as an MP4 animation) displayed the smoke plume and “hot spots” (black to yellow to red pixels) associated with the West Mims Fire that was burning in far southeastern Georgia on 25 April 2017 (this fire complex had been burning since 06 April, during which time the drought conditions had been worsening across that region). Downwind of the fire, in far northeastern Florida, smoke reduced the surface visibility to 2 miles at Jacksonville and 5 miles at Fernandina Beach.
During the subsequent nighttime hours — as the fires were beginning to decrease in both intensity and areal coverage — a comparison of “Snow/Ice” Near-Infrared (1.61 µm), “Cloud-Top Phase” Near-Infrared (2.24 µm) and Shortwave Infrared (3.9 µm) images (below; also available as an MP4 animation) showed that a bright glow from the most intense fires was evident in both of the Near-Infrared spectral bands.
Although the spatial resolution of the 1.61 µm Band 5 is 1 km (at satellite sub-point) versus 2 km for the 2.24 µm Band 6, the bright nighttime fire signature was more defined on the 2.24 µm imagery; this is explained by examining a plot of the Spectral Response Function (SRF) for each band (below; courtesy of Mat Gunshor, CIMSS). For a very hot fire target — represented by the red 1200 K line — the 2.24 µm Band 6 SRF is located near the peak of the 1200 K curve, so more of the fire-emitted radiance can be sensed by Band 6 (in spite of its lower spatial resolution).