Meteorologists Monitor Meteor

September 29th, 2021 |

According to the JPL site, there was a bright meteor (or bolide) on September 29, 2021 over the Gulf of Alaska. (The JPL and a similar NASA site are posted under the GLM tab on this link of links.) This event was seen by both the ABI and GLM on NOAA‘s GOES-17, as well as the AHI on Japan’s Himawari-8. What may be unique about his event is that the imagers monitored the meteor soon after it’s explosion, and not just the resulting plume (as was done in this case over Russia in 2013). This is based on the length of the event, during which the various spectral bands displayed a signature and other information.

Peak Brightness DatePeak Brightness Time (UT)Latitude (deg.)Longitude (deg.)Altitude (km)Total Radiated Energy (J)Calculated Total Impact Energy (kt)
2021-09-29 10:50:5953.9N148.0W2813.7e100.4

Entry from table via the JPL site.

GOES-17

The GLM and ABI observed this event, but given it’s faster readout, the GLM offers much more information than the ABI. The apparent location of the meteor as seen by the ABI is different than the reported location, in part due to parallax. More on the concept of parallax is available here.

Animation of GOES-17 ABI band 12 (9.6 mirometer) mesoscale sector #2 on September 29, 2021.

Hotter brightness temperatures can be seen in the GOES-17 ABI band 12 at 10:50:59 UTC.

Animation of all 16 bands of the GOES-17 imager on September 29, 2021. Note band 12.

Indicative of a short duration event, coupled with how the ABI scans, the meteor signature was only clearly seen at one time in nearly every ABI spectral band (although possibly the ABI band 11 as well). Due to the layout of the focal plane array on the ABI, not all spectral bands observe the Earth at the precisely same time. [Figure a modification from the GOES-R Series Data Book.] A similar loop as above, but as an animated gif, is available here. In addition,. while a bit hard to see, the longwave split window infrared difference also showed a subtle signature of the meteor.

Spectral difference images (over time) can also be useful in the monitoring of meteors. An ABI 10.3 – 12.3 micrometer band difference is shown below. An shortwave minus longwave difference loop.

An animation of the GOES-17 difference image between ABI 10.3 – 12.3 micrometer bands. The brightness temperature range is -5 to +5K.

The GLM on GOES-17 also observed this event. A similar loop as below, but as an animated gif, is available.

ABI band 12 and the GLM Flash Event Group density on September 29, 2021. Credit: CIRA/RAMMB Slider.

The rapid movement of the meteor to the south is clearly evident. As well as the GLM group map and the key (blue is early times and red is later times).

GOES-17 GLM meteor location over time and space on September 29, 2021 with larger circles (color coded to intensity). Credit: Todd Beltracchi.

As well as the changes over time, most likely monitoring the meteor break-ups.

GOES-17 GLM meteor over time on September 29, 2021. Credit: Todd Beltracchi.

More on the GLM’s light curves from NASA AMES.

AHI

Both the ABI and Japan’s AHI scan space around the edge of the Earth. However, with the ABI data the process of making calibrated, navigated, and remapped radiance only pixels located on the Earth are included in the Level 1b radiance files. Hence, the ABI may scan meteors in space, but the data are not available to most users.

All 16 spectral bands from Himawari-8 AHI at the same nominal time (10:50 UTC) on September 29, 2021.

A similar loop as above, but as an animated gif, is available here (and an 8-panel AHI image at this same time is available here). This example helps to illustrate that each AHI detector doesn’t sense radiation from the same exact location at the same time.

H/T

NOAA GOES17 data were accessed via the University of Wisconsin-Madison SSEC Satellite Data Services. McIDAS-X and Geo2Grid was used to generate imagery. Thanks also to Todd Beltracchi and Scott Bachmeier, and to CIRA/RAMMB Slider images/movies.

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