When is an ABI hot (bright) spot not a fire?

May 30th, 2020 |

An ABI hot (bright) spot is not a fire when it’s a fleet of solar farms. For example, recall the CIMSS Satellite Blog entry regarding solar farms in California. 

ABI band 2 visible

ABI band 2 visible animation on May 30, 2020 (mostly) in southeastern Minnesota. Click to play mp4.

Note how some reflections are so bright that the ABI reports dark surrounding pixels. This is part of the remapping process from detector to pixel space. 

 

9-panel

A multiple-spectral ABI comparison on May 30, 2020. The rows are: band 2, band 5, band 6 band 7, band 7 – 14 brightness temp, band 14 fire mask, band 7-14 radiance difference, band 7-14 radiance difference minus the rolling average

From left to right, top to bottom the panels are:
1) ABI band 2 reflectance, dynamically scaled to enhance contrast (will appear to flicker)
2) ABI band 5 reflectance, dynamically scaled to enhance contrast (will appear to flicker)
3) ABI band 6 reflectance, dynamically scaled to enhance contrast (will appear to flicker)
4) ABI band 7 brightness temperature, dynamically scaled to enhance contrast (will appear to flicker)
5) ABI band 7 minus band 14 brightness temperature. Red indicates positive values (extra thermal energy due to the sun and fires, if present), dynamically scaled to enhance contrast (will appear to flicker)
6) ABI band 14 brightness temperature, dynamically scaled to enhance contrast (will appear to flicker)
7) ABI Fire Detection and Characterization Algorithm (FDCA, aka WFABBA) fire detection metadata mask.  Fires are red, orange, magenta, and shades of blue indicating different confidence levels.  Green indicates fire-free land, shades of gray indicate clouds, dark  blue indicates water.
8) Radiance difference of band 7 minus band 14 radiance in band 7 space.  Red indicates positive values (extra thermal energy due to the sun and fires, if present), dynamically scaled to enhance contrast (will appear to flicker)
9) Radiance difference of band 7 minus band 14 radiance in band 7 space minus a rolling average of the 5 prior frames, to highlight changes. Red indicates positive values (extra thermal energy due to the sun and fires, if present), dynamically scaled to enhance contrast (will appear to flicker).

Aside from the solar farms, water clouds show up in the difference panels due to their reflection of shortwave radiation. 

H/T to Chris Schmidt for the 9-panel ABI imagery.  More about quantitative ABI products, including fire detection. 

The original tweet from the La Crosse WFO: “We saw some awfully bright looking “clouds” showing up via satellite in southeast Minnesota earlier this afternoon. Well after some investigation, we were able to determine they were actually solar panel arrays that the sun was hitting just right!”

NWS tweet

Solar farms and GOES-16 ABI visible imagery from the La Crosse NWS WFO.

1985 (May 31st) Tornado Outbreak as seen from GOES-6

May 26th, 2020 |

The visible and infrared bands from GOES-6 observed the historic (31 May 1985) tornado outbreak over Pennsylvania and other parts of the Northeast. For the IR band, the coldest cloud-top temperatures are highlighted with colors. Here’s is a visible animation a bit more zoomed in.

A GOES-6 visible loop, starting at 11:00 UTC on May 31, 1985 (and ends at 01:00 UTC on June 1, 1985):

A similar  GOES-6 visible loop, but a bit more zoomed in. Loop starting at 11:00 UTC on May 31, 1985 (and ends at 01:00 UTC on June 1, 1985):

A GOES-6 infrared loop, starting at 11:00 UTC on May 31, 1985 (and ends at 00:30 UTC on June 1, 1985):

 

Fade between a GOES-6 Visible and Infrared band:

https://cimss.ssec.wisc.edu/satellite-blog/images/2020/05/goes6_PA_1985_fader.html

Swipe” between a GOES-6 Visible and Infrared band:

https://cimss.ssec.wisc.edu/satellite-blog/images/2020/05/goes6_PA_1985_swiper.html

 

NOAA GOES-6 data are via the University of Wisconsin-Madison SSEC Satellite Data Services.

More on this case, from Wikipedia and NOAA’s NWS.

A View of the Development of Geostationary Imagers through the lens of BAMS

May 14th, 2020 |

A collection of 60 BAMS covers spanning the years, to highlight the rapid advance of imaging from the geostationary orbit, is shown above (a version that loops more slowly can be seen here). The first cover is the first of BAMS, in January of 1920, while the second, from January of 1957 is the first time artificial ‘satellite’ was in a title of a BAMS article. The third image, from November of 1957, is a remarkable article on potential uses of satellites. This included both qualitative uses: (1) Clouds, (2) Cloud Movements, (3) Drift of Atmospheric Pollutants, (4) State of the Surface of the Sea (or of Large Lakes), (5) Visibility or Atmospheric Transparency to Light — and quantitative uses: (1) Albedo, (2) Temperature  of  a  Level  at  or  Near  the Tropopause, (3) Total Moisture Content., (4) Total  Ozone  Content, (5) Surface  (Ground-Air Interface) Temperature, and (6) Snow Cover. Early covers showcase rockets, balloons and high-altitude aircraft to prepare the way to human space travel (Gemini, Apollo, etc.), polar-orbiters (TIROS, NIMBUS, VHRR, NOAA, etc.) and finally geostationary orbit (ATS-1, ATS-3, SMS, GOES, Meteosat, INSAT, Himawari, etc.).

Reasons to look back at the BAMS covers:

Interactive web page, with links to the original “front matter”.

Montage of select BAMS covers

Montage of select BAMS covers

Note: All cover images are from the Bulletin of the American Meteorological Society.

What has the Large Iceberg (A68) been up to this year?

March 31st, 2020 |

GOES-16 True Color RGB images [click to play animation]

GOES-16 True Color RGB images [click to play animation | MP4]

A very large iceberg broke off the Larsen-C Ice Shelf on the Antarctic Peninsula in July 2017 (recall this CIMSS Satellite Blog post). While NOAA’s GOES-16 ABI visible sensors may not be ideal, they can monitor the iceberg’s location if the cloud cover is not too thick. The animation above shows the first 31 days of 2020, with just one image per day. More information from the National Ice Center.

H/T to @annamaria_84 for this tweet using Sentinel3 images:

 

———–Update————————————-

Here’s a similar loop (mp4), but showing hourly GOES-16 “natural color” (composite) imagery, click to play animation: