Mesospheric airglow waves over the Northern Plains
Kudos to Carl Jones (NWS Grand Forks) for spotting this vivid example of mesospheric airglow waves (reference) produced by severe thunderstorms that were responsible for a swath of hail across South Dakota from 0515-1010 UTC on 02 September 2019. In the toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 (at 0740 UTC), Suomi NPP (at 0831 UTC) and NOAA-20 (at 0921 UTC), note that the epicenter of the circular gravity wave patterns appeared to be located west of the convection on the earliest NOAA-20 image and east of the convection in the later NOAA-20 image — this is due to parallax (since the vertically-propagating waves were likely at an altitude near 90 km). This parallax shift was more pronounced in the NOAA-20 images since the high-altitude waves were near the limb of those two satellite swaths. The Moon was in the Waxing Crescent phase (at only 6% of Full), so features seen on the Day/Night Band images were primarily illuminated by airglow.Closer views centered on the convection are shown below. Cloud-top infrared brightness temperatures in both South Dakota and Nebraska were -70ºC and colder in the NOAA-20 images (which are mislabeled as Suomi NPP), and -80ºC and colder in the Suomi NPP image. Bright white “lightning streak” signatures associated with the thunderstorms were more apparent in these closer views.
Interesting! Day Night Band from #SuomiNPP and #NOAA20 #VIIRS early this morning caught stunning mesospheric gravity waves. But why they are so far displaced to the west from likely culprit convection in central SD and NE? Skeptical its due to parallax. @CIMSS_Satellite pic.twitter.com/ZmL1fcXB1L
— Carl Jones (@northflwx) September 2, 2019