By Scott Bachmeier •
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.Categories: Aviation, GOES-16, MODIS, RealEarth, Red-Green-Blue (RGB) images, Suomi NPP, Terra, VIIRS