A toggle between 250-meter resolution Terra MODIS True-color and False-color Red-Green-Blue (RGB) images from the MODIS Today site (above) revealed numerous aircraft “hole punch” and dissipation trail or “distrail” features over Illinois, Indiana and Ohio on 21 December 2017.  These cloud features were caused by aircraft that were either ascending or descending through a layer of cloud composed of supercooled water droplets — cooling from wake turbulence (reference) and/or particles from the jet engine exhaust acting as ice condensation nuclei causes the small supercooled water droplets to turn into larger ice crystals (many of which then fall from the cloud layer, creating “fall streak holes“). The ice crystal clouds appear as darker shades of cyan on the false-color image.

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images showed the hole punch and distrail features over Illinois/Indiana (above) and over Indiana/Ohio (below). The glaciated (ice crystal) hole punch and distrail clouds appeared dark gray on the Snow/Ice images (since ice is a strong absorber of radiation at the 1.61 µm wavelength).

RealEarth is used to display Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.9 µm), Near-Infrared (1.61 µm), True-color and False-color RGB images at 1841 UTC (below). O ne the Shortwave Infrared images, the hole punch and distrail features are colder (brighter white) than the surrounding supercooled water droplet cloud deck — since water droplet are effective absorbers of incoming solar radiation, such clouds appear warmer (darker gray) in 3.9 µm images.

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The Southern Hemisphere Summer Solstice (and the Northern Hemisphere Winter Solstice) occurred at 1628 UTC on 21 December 2017. A 24-hour animation of GOES-16 Full Disk “Red” Visible (0.64 µm) images ending just after the Solstice time (above) showed that the far southern latitudes remained illuminated during the entire time.

Close-up views of the far Southern Hemisphere portion of the GOES-16 Full Disk are shown using “Red” Visible (0.64 µm) images (above) and Near-Infrared “Snow/Ice” (1.61 µm) images (below). The most prominent feature was the cloud shield of a 960 hPa storm system (surface analysis) moving west of the Antarctic Peninsula and over the Bellingshausen Sea — on the Snow/Ice images, clouds composed of ice crystals appear as darker shades of gray. At the end of each animation, land-fast sea ice can be seen extending northward from the Antarctic coast in the lower left portion of the images (ice appears bright white on the Visible imagery, and dark gray on the Snow/Ice imagery). In the lower center portion of the images, bright sun glint off ice-free water is apparent on 21 December at 0445 and 0500 UTC.

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GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (above) revealed a number of aircraft “hole punch clouds” and cloud dissipation or “distrail” features drifting eastward across southern Lake Michigan and adjacent states on 20 December 2017. These cloud features were caused by aircraft that were either ascending or descending through a layer of cloud composed of supercooled water droplets — cooling from wake turbulence (reference) and/or particles from the jet engine exhaust acting as ice condensation nuclei cause the small supercooled water droplets to turn into larger ice crystals (many of which then often fall from the cloud layer, creating “fall streak holes“). The darker gray appearance of the hole punch clouds on 1.61 µm images confirms that the features were composed of ice crystals (since ice is a strong absorber of radiation at that wavelength).

A good example of a hole punch cloud adjacent to a longer distrail feature was seen over far southeastern Minnesota and the Minnesota/Wisconsin border, using 250-meter resolution Aqua MODIS true-color and false-color Red-Green-Blue (RGB) images from the MODIS Today site (below). Glaciated (ice crystal) cloud features appeared as darker shades of cyan in the false-color image.

A very detailed view of a hole punch cloud over Lake Michigan was provided by 30-meter resolution Landsat-8 false-color imagery at 1635 UTC, viewed using RealEarth (below).

===== 21 December Update =====

Another example of numerous aircraft hole punch and distrail cloud features was seen on Terra MODIS true-color and false-color RGB images on 21 December. over northern Illinois and northern Indiana (below).

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The Bezymianni volcano on Russia’s Kamchatka Peninsula erupted at 0345 UTC on 20 December 2017 — an animation of Himawari-8 Infrared Window (10.4 µm) images and retrieved Ash Cloud Height product from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) indicated that the ash reached heights of 18 km (the Tokyo VAAC estimated the ash height to be 50,000 feet or 15.2 km).

An oblique view using GOES-15 (GOES-West) Visible (0.63 µm) images (below) provided a different perspective of the volcanic cloud immediately following the eruption. The surface report from Shemya (PASY), located in the far western portion of Alaska’s Aleutian Islands, is plotted in the lower right corner of the images.

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