The corresponding GOES-13 infrared (10.7 µm) images (below; click image to play animation) showed that cloud-top IR brightness temperatures were as cold a -53º C (orange color enhancement) at 1915 UTC.The volcanic cloud features were also easily tracked on GOES-13 water vapor (6.5 µm) images (below; click image to play animation). In fact, note how the signature in the water vapor imagery is more distinctly seen for a longer period of time than on the 10.7 µm infrared imagery. The tan-colored volcanic ash cloud was also evident on Aqua MODIS and Suomi NPP VIIRS true-color Red/Green/Blue (RGB) imagery (below), as viewed using the SSEC RealEarth web map server. A comparison of Suomi NPP VIIRS visible (0.64 µm) and infrared (11.45 µm) images is shown below (courtesy of William Straka, SSEC). The coldest cloud-top IR brightness temperature was -72.7º C.
The flight positions of Delta 1889 are superimposed on a composite animation of GOES-13 Infrared (10.7 µm)and Goodland, Kansas radar reflectivity, below (courtesy of Rick Kohrs, SSEC).
The 2015 Wildfire Season is off to a quick start in Alaska (continuing an observed trend). This map (from this site) shows more than 300 active fires over Alaska at 2000 UTC on 29 June 2015. This graph (from the Alaska Climate Info Facebook page) compares early burn acreage in 2015 to that in 2004 (the year with the most acreage burned — see this graph, courtesy of Uma Bhatt, University of Alaska-Fairbanks).
Soumi NPP VIIRS 3.74 µm infrared imagery from early morning on 29 June 2015 (top) shows numerous wildfire hot spots (dark black pixels) in the region surrounding the Yukon River (the middle portion of the imagery, south of Kotzebue Sound). VIIRS visible imagery from the same time, above, shows an extensive pall of smoke over much of central Alaska.
Meanwhile, thick smoke from fires burning over northern Canada (comparison of VIIRS visible and shortwave IR images from 28 June) was drifting southward over central portions of the Lower 48 states. The smoke plume on 28 June (above) was fairly narrow; however, a much broader and thicker plume was seen moving south on 29 June (GOES visible imagery below, then MODIS/VIIRS true-color RGB imagery as displayed using the SSEC RealEarth web map server). SSEC MODIS Today true-color imagery of this smoke plume is also available here. Pilot reports placed the lower and upper bounds of the thick smoke at 5000 and 17500 feet, with flight visibilities as low as 2 miles at 5000 feet. Some of the smoke subsided to the surface in southeastern South Dakota, restricting the surface visibility at Sioux Falls to 5 miles and raising the Air Quality Index there into the Unhealthy category. In fact, the smoke was so thick over far eastern South Dakota that it had the effect of reducing surface heating and slowing the rise of afternoon temperatures, such that convective temperatures were not being reached and probabilities of precipitation had to be scaled back:
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
356 PM CDT MON JUN 29 2015
.SHORT TERM…(THIS EVENING THROUGH TUESDAY)
ISSUED AT 356 PM CDT MON JUN 29 2015
IN ADDITION…THICK PLUME OF SMOKE CONTINUES TO DRIFT SOUTHWARD IMPACTING NEARLY ALL OF THE FORECAST AREA…BUT MOST NOTABLE ALONG AND EAST OF THE JAMES RIVER VALLEY. BECAUSE OF THIS…AFTERNOON TEMPERATURES ARE ABOUT 2 TO 4 DEGREES
COOLER THAN FORECAST AND WE ARE HAVING A HECK OF A TIME REACHING OUR CONVECTIVE TEMPERATURE. THEREFORE LOWERED THE LATE AFTERNOON AND EVENING POPS IN OUR EASTERN ZONES TO ONLY SLIGHT CHANCE POPS. BUT EVEN THOSE MAY BE TOO HIGH AND IF NOTHING DEVELOPS OVER THE NEXT COUPLE OF HOURS…THEY MAY NEED TO BE REMOVED ENTIRELY.
Daytime detection of smoke plumes is not difficult with visible (or true-color) imagery. At night, however, smoke detection is a challenge. The VIIRS Day/Night Band on Suomi NPP can detect smoke when Lunar Illumination is high (although detection is limited to one or sometimes two passes per night). Smoke is otherwise mostly transparent to infrared channels on the GOES Imager. Websites such as the NOAA/NESDIS IDEA and the GASP are helpful; however, the GASP product uses single-channel (visible) detection only.
Visible imagery from GOES-15, below, highlights the expansive region covered by smoke over northern Canada. Note that the smoke becomes less distinct with time as the sun rises higher in the sky, because forward scattering of visible light by smoke particles is more effective than backward scattering.
Singapore Airlines Flight SQ836 was en route to Shanghai from Singapore on 23 May 2015 when it lost power from both engines at an altitude of 39,000 feet over the South China Sea, not far south-southeast of Hong Kong (Aviation Herald). The aircraft lost about 13,000 feet in altitude (above) before the engines were successfully re-started. The violet portion of the flight path denotes the period when no ADS-B data were received, from 1246 to 1311 UTC.
Himawari-8 AHI 11.2 um IR channel images (above; click image to play animation; also available as an MP4 movie file) and 6.2 um water vapor channel images (below; click image to play animation; also available as an MP4 movie file) showed a broken line of vigorous deep convection to the north of where the engine power loss first occurred (approximately within the yellow circle; VHHH is the airport identifier for Hong Kong). On the IR imagery, the coldest cloud-top brightness temperatures were in the -80 to -90 C range (shades of violet), and anvil debris could be seen drifting south-southwestward. This convective cloud debris may have contributed to a phenomenon known as ice crystal icing, which affected the engines of the aircraft.