30-second GOES-16 “Red” Visible (0.64 µm) images with time-matched SPC Storm Reports plotted in red [click to play animated GIF | MP4]

Overlapping 1-minute Mesoscale Domain Sectors provided 30-second interval GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) — which showed thunderstorms that produced tornadoes, large hail (up to 4.4 inches in diameter) and damaging winds (SPC Storm Reports) across western Oklahoma on 30 April 2024. Pulses of overshooting tops and evidence of Above-Anvil Cirrus Plumes (reference | VISIT training | blog posts) were apparent in the Visible imagery.

A longer animation of 30-second GOES-16 “Clean” Infrared Window (10.3 µm) images (below) extended a few hours past sunset. The coldest overshooting top infrared brightness temperatures were in the -75 to -78ºC range (brighter shades of white).

30-second GOES-16 “Clean” Infrared Window (10.3 µm) images with time-matched SPC Storm Reports plotted in cyan [click to play animated GIF |  MP4]

Small Radiance Anomaly along the Focal Plane Array

An anomaly that’s immediately obvious is a “flicker” between Infrared images from the 2 Mesoscale Sectors (which was also evident in full bit depth AWIPS imagery). This oscillation is also seen in this McIDAS-X “radiance” animation of alternating Meso Sectors (near the top of one sector and the bottom of the other — where radiance values of 120 to 10 are mapped to brightness values from 0 to 255). This was due to combining the upper portion of Meso 1 with the lower portion of Meso 2 (figure) to create 30-second imagery; as the GOES ABI scans each Mesoscale Sector, a swath-to-swath discontinuity is mainly caused by the difference in detector response at the ends of the focal plane array (FPA) — depending on the location in the ABI field of regard (thanks to Tim Schmit, NOAA/NESDIS for tracking down the explanation for this image anomaly, which came from F. Yu, GOES Calibration Working Group). In general, the magnitude of these differences are less than 0.1 K @300 K (although for an extremely cold scene, the brightness temperature difference may be larger than 1 K). These difference values are within the ABI specification.
Note that brightness temperature discontinuities can sometimes be seen between ABI horizontal scan swaths, if the scene is very cold. One such ABI Band 13 example was seen with Hurricane Zeta (from this blog post). In addition, here’s an example from Zeta showing a scan swath discontinuity from 3 GOES-16 sectors (Full Disk, CONUS and Mesoscale).

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Farther to the north, 30-second GOES-16 Visible images centered over southern Kansas (below) also displayed pulses of overshooting tops and signatures of Above-Anvil Cirrus Plumes.

30-second GOES-16 “Red” Visible (0.64 µm) images with time-matched SPC Storm Reports plotted in red [click to play animated GIF | MP4]

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