Aircraft “distrails” over the southcentral US

January 29th, 2007 |

GOES-12 visible image

GOES-12 visible channel imagery (above; Java animation) revealed numerous aircraft dissipation trails (otherwise known as “distrails” or “hole punch clouds”) during the day over eastern Texas, northern Louisiana, southern Arkansas, and Mississippi on 29 January 2007. Corresponding GOES-12 10.7µm InfraRed (IR) imagery showed that cloud top temperatures over that region were generally between -20º and -35º C; as aircraft (likely air traffic to/from Dallas-Fort Worth airport KDFW) penetrated that supercooled cloud layer aloft, they caused the cloud droplets to glaciate and begin to fall out of the cloud (causing the “holes” and “streaks” that were evident on the visible imagery). A higher resolution view of these cloud features is available from the Terra MODIS (sourced from the NASA Rapidfire site) and Aqua MODIS overpasses. The 12 UTC rawinsonde data from Fort Worth, Texas (below) indicated that the likely elevation of the supercooled coud deck was probably around 25,000 feet or so. Photos of these cloud features can be seen on the MediaLine weather forum, Weather Underground WunderBlog, WKRG (Mobile AL), NASA Earth Observatory , and StormCenter Envirocast sites.
Fort Worth TX rawinsonde report

“Hole punch clouds” and aircraft “distrails”

November 15th, 2006 |

GOES-12 visible and shortwave IR image animation
Some interesting photos of “hole punch clouds” were captured on 15 November 2006 — the photos (which appeared on the 16 November Spaceweather.com site) were were taken at Stevens Point in central Wisconsin. A QuickTime animation of GOES-12 visible channel and 3.9µm shortwave IR images (above) revealed a series of aircraft dissipation trails (or “distrails”) drifting northeastward between Madison and Stevens Point during the day; particles in the aircraft exhaust were acting as ice nuclei, causing any supercooled cloud droplets to glaciate and also helping other existing cloud ice crystals to increase in size — these larger ice crystals then descended under the influence of gravity, creating precipitation-induced “holes” and “streaks” in the cloud layers aloft. A 500-meter resolution Aqua MODIS true color image centered on Madison shows better details of the structure of 2 of the northwest-to-southeast oriented “distrails” that were located north of Madison at the time of the satellite overpass.

Other MODIS images and products that were available on AWIPS included the 1000-meter resolution 3.7µm shortwave IR channel (below); the brighter (colder) curved cloud signature in this image suggests that one of the aircraft had recently made a loop in the area between Madison (KMSN) and Wisconsin Dells (KDLL). It is likely that military jets from Volk Field Air National Guard Base (KVOK) were performing training exercises north of Madison, with the jet exhaust helping to initiate some of the interesting cloud patterns that were visible both on the ground and via satellite.
AWIPS MODIS 3.7µm IR image

Aircraft dissipation trail in Iowa

July 28th, 2017 |

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

An aircraft “dissipation trail” formed over far southern Iowa during the late morning hours on 28 July 2017 — which was seen on GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61  µm) and Shortwave Infrared (3.9) µm) imagery (below).

GOES-16

GOES-16 “Red” Visible (0.64 µm, tpo), Near-Infrared “Snow/Ice” (1.61 µm, middle) and Shortwave Infrared (3.9) µm, bottom) images [click to play animation]

As explained in this blog post, these types of cloud features are caused by aircraft either ascending or descending through a cloud layer composed of supercooled water droplets. Cooling from wake turbulence (reference) — and/or the particles from the jet engine exhaust acting as ice condensation nuclei — then cause the small supercooled water droplets to change phase and transform into larger ice crystals (which often fall from the cloud layer, creating “fall streak holes“).

Therefore, the glaciated aircraft dissipation trail appears darker on the 1.61 µm “snow/ice” images (since ice is a strong absorber of radiation at that wavelength), and colder (brighter white) on the 3.9 µm shortwave infrared images.

Aircraft “hole punch” and “dissipation trails” over the eastern Great Lakes

March 3rd, 2016 |

GOES-13 (GOES-East ) Visible (0.63 µm) images centered over Lake Erie, Lake Ontario, and central New York state (below) showed a variety of aircraft “hole punch” and “dissipation trails” over the eastern Great Lakes on 03 March 2016.

GOES-13 Visible (0.63 µm) images, centered over Lake Erie [click to enlarge]

GOES-13 Visible (0.63 µm) images, centered over Lake Erie [click to play animation]

GOES-13 Visible (0.63 µm) images, centered over Lake Ontario [click to play animation]

GOES-13 Visible (0.63 µm) images, centered over Lake Ontario [click to play animation]

GOES-13 Visible (0.63 µm) images, centered over New York state [click to play animation]

GOES-13 Visible (0.63 µm) images, centered over New York state [click to play animation]

These cloud features were caused by aircraft that were either ascending or descending through layers of cloud composed of supercooled water droplets, which covered much of the region as shown by the POES AVHRR Cloud Type product at 1545 UTC (below). Cooling from wake turbulence (reference) and/or the particles from the jet engine exhaust acting as ice condensation nuclei cause the small water droplets to turn into larger ice crystals (which then often fall from the cloud layer, creating “fall streak holes“). Similar features have been discussed in previous blog posts.

POES AVHRR Cloud Type product at 1545 UTC [click to enlarge]

POES AVHRR Cloud Type product at 1545 UTC [click to enlarge]

There were numerous pilot reports of light to moderate icing between FL120 and FL160 (flight level 12,000-16,000 feet) when passing through the supercooled water droplet cloud layers (below). The pilot report altitudes agree well with the POES AVHRR Cloud Top Height product values of 4-5 km over Lake Erie at 1545 UTC.

GOES-13 Visible (0.63 µm) images with pilot reports of icing [click to play animation]

GOES-13 Visible (0.63 µm) images with pilot reports of icing [click to play animation]

A comparison of 250-meter resolution Terra MODIS true-color and false-color Red/Green/Blue (RGB) images at 1649 UTC as visualized using RealEarth (below) indicated that the cloud material in the center of the aircraft dissipation trail over the north shore of Lake Erie had glaciated (snow, ice, and ice crystal clouds exhibit a darker cyan appearance on the false-color image).

Terra MODIS true-color and false-color images over Lake Erie [click to enlarge]

Terra MODIS true-color and false-color images over Lake Erie [click to enlarge]

A panorama photo from the ground was taken in Binghamton, New York (station identifier KBGM, located near the center of the New York GOES-13 images):