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):


GOES-14 SRSO-R: aircraft “hole punch clouds” in North and South Carolina

February 9th, 2016 |

GOES-14 Visible (0.63 µm) images [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images [click to play MP4 animation]

1-minute interval GOES-14 Super Rapid Scan Operations for GOES-R (SRSO-R) Visible (0.63 µm) images (above; also available as a large 71 Mbyte animated GIF) revealed the formation of clusters of aircraft “hole punch clouds” over central North and South Carolina on the morning of 09 February 2016. These types of cloud features form when aircraft fly through a layer of clouds composed of supercooled water droplets; cooling from wake turbulence (reference) and/or the particles from the jet engine exhaust which may act 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.

A comparison of GOES-14 Visible (0.63 µm, 1-km resolution) and Shortwave Infrared (3.9 µm, 4-km resolution) images (below; also available as a large 71 Mbyte animated GIF) offered evidence that the cloud material within each “hole punch” was composed of ice crystals, which exhibited colder (lighter gray) IR brightness temperatures than the surrounding supercooled water droplet clouds. It is likely that many of the hole punch features were caused by aircraft ascending from or descending to the Charlotte Douglas International Airport in North Carolina (KCLT).

GOES-14 Visible 0.63 µm (left) and Shortwave Infrared 3.9 µm (right) images [click to play MP4 animation]

GOES-14 Visible 0.63 µm (left) and Shortwave Infrared 3.9 µm (right) images [click to play MP4 animation]

In a comparison 1-km resolution POES AVHRR Visible (0.86 µm) and Infrared (12.0 µm) images (below), the cloud-top IR brightness temperatures in the vicinity of the hole punch features were only as cold as -20 to -24º C (cyan to blue color enhancement), which again is supportive of the cloud layer being composed of supercooled water droplets.

POES AVHRR Visible 0.86 µm) and Infrared (12.0 µm) images [click to enlarge]

POES AVHRR Visible 0.86 µm) and Infrared (12.0 µm) images [click to enlarge]

Aircraft dissipation trails and “hole punch clouds” over Florida

December 12th, 2014 |
GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

McIDAS images of 1-km resolution GOES-13 0.63 µm visible channel data (below; click image to play animation; also available as an MP4 movie) revealed numerous aircraft dissipation trails and “hole punch clouds” which formed over southern Florida and the adjacent waters of the Atlantic Ocean on 12 December 2014. These features are formed when an aircraft penetrates a supercooled cloud layer — the particles in the exhaust act as ice nuclei which allow the supercooled water droplets to transform into ice crystals.

A comparison of 250-meter resolution Terra MODIS true-color and false-color Red/GreenBlue (RGB) images from the SSEC MODIS Today site (below) confirmed that the clouds within the dissipation trails and the hole punch features had glaciated — ice crystal clouds appear as shades of cyan in the false-color image, in contrast to supercooled water droplet cloud which appear as varying shades of white.

Terra MODIS true-color and false-color images

Terra MODIS true-color and false-color images