Aircraft dissipation trails over the Lake Ontario region

November 4th, 2013 |
GOES-13 0.63 µm visible channel images (click to play animation)

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

Hat tip to NWS Buffalo NY forecasters Jon Hitchcock and David Zaff for letting us know about a number of aircraft dissipation trails (also known as “distrails” or “hole punch clouds”) over the Lake Ontario region on 04 November 2013. A series of McIDAS images of 1-km resolution GOES-13 0.63 µm visible channel data (above; click image to play animation) showed these features as they drifted eastward during the day.

A comparison of AWIPS II images of 375-meter resolution Suomi NPP VIIRS 0.64 µm visible channel data and the corresponding false-color”Snow Cloud Discrimination” Red/Green/Blue (RGB) product at 18:17 UTC (below) indicated that the cloud layer penetrated by the aircraft was composed of supercooled water droplets (which appear brighter on the RGB image) — but the particles in the aircraft exhaust acted as ice nuclei and caused the cloud to glaciate (ice crystal clouds appear as varying shades of red on the RGB image).

Suomi NPP VIIRS 0.64 µm visible channel and

Suomi NPP VIIRS 0.64 µm visible channel and “Snow Cloud Discrimination RGB” images

AWIPS images of the POES AVHRR CLAVR-x Cloud Type product confirmed that the cloud layer over the Lake Ontario region was a supercooled water droplet cloud (green color), with the Cloud Top Height product indicating tops in the 7-9 km range (below). However, higher-altitude cirrus clouds were beginning to overspread the region from the west (cirrus=orange; thick ice=yellow; overlap=violet).

POES AVHRR 0.86 µm visible channel image, Cloud Type product, and Cloud Height produc

POES AVHRR 0.86 µm visible channel image, Cloud Type product, and Cloud Height product

 

Tracking a Lunar Umbra (solar eclipse shadow) across the Atlantic Ocean

November 3rd, 2013 |
Meteosat-10 0.635 µm visible channel images (click to play animation)

Meteosat-10 0.635 µm visible channel images (click to play animation)

A rare “hybrid” solar eclipse occurred on 03 November 2013 (photos), which began over the western Atlantic Ocean as an annular eclipse and transitioned into a full total solar eclipse for observers along the narrow path of totality in the far eastern Atlantic and over parts of Africa (map of eclipse path). The Lunar Umbra (or solar eclipse shadow) could be seen tracking rapidly southeastward across the Atlantic Ocean on EUMETSAT Meteosat-10 0.635 µm visible channel images from 10:45-14:30 UTC (above; click image to play animation).

The dark solar eclipse shadow could also be seen near the edge of the Full Disk scan of the GOES-13 satellite at 11:45 UTC, just south and southwest of the Cape Verde Islands (below). Since the current generation of GOES only perform a full disk scan once every 3 hours,  the eclipse shadow could not be followed in time as it was using the 15-minute interval images from Meteosat-10.

GOES-13 0.63 µm visible channel images

GOES-13 0.63 µm visible channel images

With the next-generation GOES-R series, a full disk scan will occur once every 5 minutes. As a part of the GOES-14 Super Rapid Scan for GOES-R (SRSOR) testing, full disk scans were performed every 30 minutes on 14 September 2012.