1-minute Mesoscale Domain Sector GOES-16 (GOES-East) Dust RGB images (above) displayed signatures of blowing dust (brighter shades of pink) moving southward across eastern Colorado and over the Oklahoma/Texas Panhandle region on 23 December 2020. The dust source region appeared to be eastern Colorado, where wind gusts in excess of 60 knots were observed during the morning hours.

GOES-16 True Color RGB images created using Geo2Grid (below) showed the lighter tan colored signature of these areas of blowing dust.

Additional details of this event are available on the Satellite Liaison Blog.

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Strong winds behind a storm moving along the United States/Canada border on 23 December 2020 led to blizzard warnings over much of the Northern Plains (link). How easily was the blowing snow detected by satellite?

The animation above shows the Day Snow Fog RGB from 1416 through 1751 UTC on 23 December 2020. During this time over North Dakota, low clouds (bright whitish/periwinkle) and mid/high-level clouds (transparent violet) masked the surface from the satellite view. However, blowing snow is suggested to the south of Lake Manitoba. The RGB has a slightly different, brighter color than the adjacent snow-cover — that is red — and the texture in the image, and the linear features aligned with the wind both suggest lofted blowing snow.

The VIIRS instruments on board Suomi-NPP and NOAA-20 also viewed this scene, once at 1759 UTC (from NOAA-20) and once at 1850 UTC (from Suomi-NPP), with much higher spatial resolution. There is a region of enhanced reflectance (i.e., whiter shades of grey) in the 1.61 µm imagery to the south-southeast of Lake Manitoba in the top center of the image.  These are lofted, fractured ice crystals that are more reflective of solar radiation than surrounding snow cover.  The signal shows up in the False Color imagery as well, but not in the true color imagery that does not incorporate information from the 1.61 µm channel.  A similar signal appears in extreme northeast North Dakota at 1759 UTC.  VIIRS imagery does not suggest widespread blowing snow.  Indeed, snow depths over North Dakota suggest little snow on the ground to blow around (snow depth analysis, from this site)!  Snow depths over Manitoba are a bit larger.

The animation from 1751 UTC to 2106 UTC on 23 December, below, which animation includes the times of the VIIRS overpasses above, also captures the snow plume downwind of Lake Manitoba, extending to the North Dakota/Minnesota border and, perhaps, into northwestern Minnesota. However, clouds over Minnesota (and the Red River of the North) make definitive blowing snow detection difficult. Traffic webcams as a supplement to the satellite data source will create a better feel for the horizontal extent of the blowing snow.

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This 11-minute training video discusses this RGB’s abilities in blowing snow detection in a bit more depth.  You can view a longer presentation concerning othis RGB here.

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GOES-17 (GOES-West) Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.35 µm) images (above) displayed the thermal anomaly (cluster of hot pixels) and brief volcanic cloud resulting from an eruption of the Kilauea volcano on the Big Island of Hawai’i on 21 December 2020. The coldest cloud-top 10.35 µm infrared brightness temperature was -34.6ºC at 0840 UTC — which roughly corresponded to the 300 hPa or 9.6 km altitude according to 12 UTC rawinsonde data from nearby Hilo (plot | text). However, this volcanic cloud quickly dissipated in the very dry air aloft.

GOES-17 Near-infrared (1.61 µm and 2.24 µm) and Shortwave Infrared images (below) showed the variation in thermal signatures during the hours leading up to sunrise. The signature in Near-Infrared imagery was occasionally attenuated by the passage of trade wind cumulus clouds over the eruption site.

A comparison of Suomi NPP VIIRS Near-infrared (1.61 µm and 2.25 µm), Shortwave Infrared (3.75 µm) and Day/Night Band (0.7 µm) images (below) provided a high spatial resolution view of the thermal and emitted light signatures of the ongoing eruption at 1221 UTC.

A larger-scale view of GOES-17 Shortwave Infrared, SO2 RGB and Ash RGB images (below) showed the southward transport of a mid/high-altitude plume of SO2 (lighter shades of yellow to cyan) from the initial eruption, followed by the southwestward transport of a more persistent low-altitude plume of SO2 as the eruption continued during the day. No signature of volcanic ash was indicated (either qualitatively on the Ash RGB images, or on retrieved ash products from this site). At times the thermal anomaly of the eruption site exhibited 3.9 µm infrared brightness temperatures as hot as 105ºC.

GOES-17 True Color RGB images created using Geo2Grid (below) displayed the volcanic fog (or “vog”) plume that moved southwestward during the day — a portion of which became entrained into the circulation of a lee-side cyclonic gyre southwest of the Big Island.

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By animating daily NOAA GOES-16 ABI Full Disk visible imagery, how the Earth is illuminated over time can be seen. For example, the minimum in incoming solar radiation in the Northern Hemisphere associated with the Winter Solstice. For details, see “What is a Solstice?” by SciJinks. Or this NOAA https://www.noaa.gov/education/news/share-your-solstice-sunset-with-noaa-education post.

A Full Disk visible (band 2) loop at 11 UTC, (9 and 18 sec long versions).

Interactive web pages

An interactive web page with a years worth of GOES ABI Full Disk visible images at 11 UTC. The beginning date is the (northern hemisphere) winter solstice is 2019 and the end date is the winter solstice in 2020. A user can play the animation, as well as annotate the images. For example, draw lines along the terminator for different times of the year. One example might be to compare a solstice to an equinox. H/T Tom Whittaker, SSEC, for the webapp.

 

The Year in Review

A year-long Midwest CIMSS (Natural) true color (during the day) and the nighttime cloud microphysics) animation from GOES-16 at 18 UTC. Since this are daytime images, only the true color is being seen. A similar loop as above, but with a duration of 37 sec or 74 sec.

Year-long, GOES-16 loops at 18 UTC have been generated for other regions, including: the Northeast, Mid-Atlantic, Southeast, Texas and part of the Gulf of Mexico, Central US, Southwest, and Northwest. Similar loops from GOES-17 have been generated using images from 21 UTC for both Alaska and Hawaii. Note for the loop over parts of Alaska, the nighttime imagery is evident. These loops begin on the Winter Solstice 2019.

Year-long Hourly Loop over the Midwest

A very large (800 MB) file, showing a year-long (hourly) GOES-16 file over the Midwest (duration of 14 min). The loop is also on YouTube. Many features can be seen, including clouds, smoke and snow. This loop begin on the Winter Solstice 2019.

These images were made with either McIDAS-X or geo2grid, both from UW-Madison, SSEC.

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