Fires in the southeast United States

November 7th, 2016 |
terramodis_truecolor_7nov2016

Terra MODIS True-Color Imagery over the Smoky Mountains, 7 November 2016 (Click to enlarge)

Persistent moderate to severe drought (shown here, from this site) over the southeastern United States has supported the development of fires in and around the Great Smoky Mountains on 7 November 2016. True-color imagery from Terra MODIS, above, (source: MODIS Today) showed the active fires and plumes of smoke spreading northward into the Ohio River Valley.

Suomi NPP VIIRS true-color imagery also captured the smoke emanating from the active fires, and the Aerosol Optical Depth product, toggled below (data sources: RealEarth) showed the extent of the thickest smoke layer (click here for an animation that does not include the RealEarth framing).

Suomi NPP VIIRS true-color image with fire detection locations (red dots), and VIIRS Aerosol Optical Depth product [click to enlarge]

Suomi NPP VIIRS true-color image with fire detection locations (red dots), and VIIRS Aerosol Optical Depth product [click to enlarge]

A sequence of true-color Red/Green/Blue (RGB) images from Terra MODIS (1643 UTC), Suomi NPP VIIRS (1809 UTC) and Aqua MODIS (1824 UTC) is shown below.

Terra MODIS, Suomi NPP VIIRS and Aqua MODIS true-color images [click to enlarge]

Terra MODIS, Suomi NPP VIIRS and Aqua MODIS true-color images [click to enlarge]

The temporal evolution of the smoke was captured on GOES-13 Visible (0.63 µm) images (below; also available as an MP4 animation). Smoke reduced the surface visibility to 2.5 – 3.0 miles at some locations in Kentucky (KJKL | KLOZ) and Tennessee (KOQT), leading to EPA Air Quality Index values in the “Unhealthy” category.

GOES-13 Visible (0.63 µm) images; hourly surface weather symbols are plotted in yellow, with surface visibility (statute miles) plotted in cyan [click to play animation]

GOES-13 Visible (0.63 µm) images; hourly surface weather symbols are plotted in yellow, with surface visibility (statute miles) plotted in cyan [click to play animation]

===== 10 November Update =====

GOES-13 Visible (0.63 µm) images; hourly surface weather symbols are plotted in yellow, with surface visibility (statute miles) plotted in cyan [click to play animation]

GOES-13 Visible (0.63 µm) images; hourly surface weather symbols are plotted in yellow, with surface visibility (statute miles) plotted in cyan [click to play animation]

In the wake of a cold frontal passage on 09 November, northerly to northeasterly winds were transporting the smoke south-southwestward as the fires continued to burn on 10 November. GOES-13 Visible (0.63 µm) images, above, showed the dense smoke plumes — some of which were briefly reducing the surface visibility to less than 1 statute mile in far western North Carolina (Andrews | Franklin). In Georgia, smoke restricted the visibility to 2.5 miles as far south as Columbus.

A Pilot Report (PIREP) in northern Georgia at 1530 UTC, below, indicated that the top of the smoke layer was around 3500 feet (where the Flight Visibility was 4 miles).  Surface reports in the vicinity of that PIREP indicated a ceiling of 1500 to 1700 feet, suggesting that the dense smoke layer aloft was about 1800-2000 feet thick over northern Georgia.

GOES-13 Visible (0.63 µm) image, with cloud ceiling (hundreds of feet above ground level) and visibility (statute miles) plotted in cyan and a Pilot Report in yellow [click to enlarge]

GOES-13 Visible (0.63 µm) image, with cloud ceiling (hundreds of feet above ground level) and visibility (statute miles) plotted in cyan and a Pilot Report in yellow [click to enlarge]

The smoke plumes showed up very well on an Aqua MODIS true-color RGB image from the MODIS Today site, below.

Aqua MODIS true-color image [click to enlarge]

Aqua MODIS true-color image [click to enlarge]

The 1858 UTC Suomi NPP VIIRS true-color image (with fire detections) and the Aerosol Optical Depth product, below, depicted the aerial coverage of the smoke.

Suomi NPP VIIRS true-color image (with fire detection locations in red) and Aerosol Optical Depth product [click to enlarge]

Suomi NPP VIIRS true-color image (with fire detection locations in red) and Aerosol Optical Depth product [click to enlarge]

Severe turbulence injures 24 on JetBlue Flight 429

August 11th, 2016 |

JetBlue Flight 429 flight path [click to enlarge]

JetBlue Flight 429 flight path [click to enlarge]

JetBlue Flight 429 encountered severe turbulence over south-central South Dakota around 0115 UTC on 12 August (7:15 pm local time on 11 August) 2016, which caused injuries to 22 passengers and 2 crew members (media story). The aircraft (flying from Boston MA to Sacramento CA) had to be diverted to Rapid City SD, as seen on the flight path map above (source: FlightAware.com).

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

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

1-km resolution GOES-13 Visible (0.63 µm) images (above) showed widespread thunderstorms across the region, with rapidly-developing new cells forming in the vicinity of the turbulence encounter. A Turbulence AIRMET had been issued around 23 UTC for that portion of the flight path, and Convective SIGMETs also advised of the potential for severe thunderstorms with tops above 45,000 feet (JetBlue 429 was cruising at an altitude of 32,000 feet).

The corresponding 4-km resolution GOES-13 Infrared Window (10.7 µm) images (below) indicated that cloud-top IR brightness temperatures were as cold as -54º C (orange color enhancement) just east of the pilot report at 0100 UTC.

GOES-13 Infrared Window (10.7 µm) images, with pilot reports of turbulence [click to play animation]

GOES-13 Infrared Window (10.7 µm) images, with pilot reports of turbulence [click to play animation]

1-km resolution POES AVHRR Visible (0.86 µm) and Infrared (12.0 µm) images at 0049 UTC (below) provided a more detailed view of the developing cells less than 30 minutes prior to the turbulence encounter.

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

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

Transverse banding: a signature of potential turbulence

July 20th, 2016 |

GOES-13 Infrared Window (10.7 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

GOES-13 Infrared Window (10.7 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

GOES-13 (GOES-East) Infrared Window (10.7 µm) images (above) showed the formation of tendrils of transverse banding along the northern semicircle of  decaying mesoscale convective systems as they moved eastward across Nebraska and Iowa on 19 July 2016. Pilot reports of turbulence are plotted on the images, along with Turbulence AIRMET polygons issued at 0800 UTC and 1400 UTC. Most of the pilot reports of turbulence were in the Light to Moderate category, although there was one report of Moderate to Severe intensity at 1612 UTC over eastern Iowa.

The corresponding GOES-13 Water Vapor (6.5 µm) images (below) perhaps highlighted the transverse banding features a bit better at times, since the weighting function for that spectral band generally peaks in the middle to upper troposphere where the transverse banding cloud features existed.

GOES-13 Water Vapor (6.5 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

GOES-13 Water Vapor (6.5 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

A sequence of Infrared Window images from POES AVHRR (10.8 µm) and Suomi NPP VIIRS (11.45 µm) (below) showed a higher-resolution view of the initial formation of transverse banding during the 0411 to 1008 UTC time period.

Infrared Window images from POES AVHRR (10.8 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

Infrared Window images from POES AVHRR (10.8 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

Shown below are two other types of satellite imagery that can be helpful for identifying the areal extent of transverse banding cloud features: the Suomi NPP VIIRS Day/Night Band (0.7 µm), and the MODIS Cirrus band (1.37 µm). A similar Cirrus band will be part of the ABI instrument on GOES-R.

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Terra MODIS Infrared Window (11.0 µm) and Cirrus (1.37 µm) images [click to enlarge]

Terra MODIS Infrared Window (11.0 µm) and Cirrus (1.37 µm) images [click to enlarge]

Eruption of the Mount Pavlof volcano in Alaska

March 28th, 2016 |

Himawari-8 AHI Shortwave Infrared (3.9 µm) images [click to play animation]

Himawari-8 AHI Shortwave Infrared (3.9 µm) images [click to play animation]

A major eruption of the Mount Pavlof volcano on the Alaska Peninsula began shortly before 0000 UTC on 28 March, or 4:00 pm on 27 March Alaska time (AVO report), as detected by a thermal anomaly (or “hot spot”, yellow to red color enhancement) on Himawari-8 AHI Shortwave Infrared (3.9 µm) images (above). The hot spot decreased in size and intensity toward the later hours of the day, signaling a lull in the volcanic eruption.

It is interesting to note on a comparison of the 0000 UTC Himawari-8 and GOES-15 Shortwave Infrared (3.9 um) images the large difference in the magnitude of the thermal anomaly — even though the viewing angle was larger for Himawari-8, the superior spatial resolution (2 km at nadir, compared to 4 km with GOES-15) detected a hot spot with an Infrared Brightness Temperature (IR BT) that was 36.6 K warmer (below). The Infrared channels on the GOES-R ABI instrument will also have a 2 km spatial resolution.

Himawari-8 AHI (left) and GOES-15 Imager (right) 3.9 µm Shortwave Infrared images [click to enlarge]

Himawari-8 AHI (left) and GOES-15 Imager (right) 3.9 µm Shortwave Infrared images [click to enlarge]

With the aid of reflected light from the Moon (in the Waxing Gibbous phase, at 75% of Full), a nighttime view using the Suomi NPP VIIRS Day/Night Band (0.7 µm) from the SSEC RealEarth site (below) revealed the bright glow of the eruption, along with the darker (compared to adjacent meteorological clouds) volcanic ash cloud streaming northeastward. The corresponding VIIRS Shortwave Infrared (3.74 µm) image showed the dark black hot spot of the volcano summit.

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) image [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) image [click to enlarge]

The volcanic ash cloud continued moving in a northeastward direction, as seen in a sequence of GOES-15 Infrared Window (10.7 µm) and either Terra/Aqua MODIS or Suomi NPP VIIRS retrieved Volcanic Ash Height products from the NOAA/CIMSS Volcanic Could Monitoring site (below).

GOES-15 Infrared (10.7 µm) images, with Terra/Aqua MODIS and Suomi NPP VIIRS Ash Height products [click to play animation]

GOES-15 Infrared (10.7 µm) images, with Terra/Aqua MODIS and Suomi NPP VIIRS Ash Height products [click to play animation]

Due to the oblique satellite view angle, the shadow cast by the tall volcanic ash cloud was easily seen on the following early morning (Alaska time) Himawari-8 AHI Visible (0.64 µm) images (below). A closer view (courtesy of Dan Lindsey, RAMMB/CIRA) revealed overshooting tops and gravity waves propagating downwind of the eruption site.

Himawari-8 AHI Visible (0.64 um) images (click to play animation]

Himawari-8 AHI Visible (0.64 um) images (click to play animation]

A few select Pilot reports (PIREPs) are shown below, plotted on GOES-15 Infrared Window (10.7 µm) and Aqua MODIS Ash Height derived products. Numerous flights were canceled as the ash cloud eventually began to drift over Western and Interior Alaska (media report).

GOES-15 Infrared Window (10.7 um) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 um) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 um) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm) image, with METAR surface reports and Pilot reports [click to enlarge]

Aqua MODIS Ash Height product, with METAR surface reports and Pilot reports [click to enlarge]

Aqua MODIS Ash Height product, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 um), with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm), with METAR surface reports and Pilot reports [click to enlarge]

A comparison of Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm), and true-color Red/Green/Blue (RGB) images (below) showed the volcanic hot spot and the brown to tan colored ash cloud at 2141 UTC on 28 March. Significant ash fall (as much as 2/3 of an inch) was experienced at the village of Nelson Lagoon, located 55 miles northeast of Pavlof (media report).

Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm), and true-color RGB images [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm), and true-color RGB images [click to enlarge]

A comparison of the 3 Himawari-8 AHI Water Vapor bands (7.3 µm, 6.9 µm and 6.2 µm) covering the first 14 hours of the eruption from 0000 to 1400 UTC is shown below. Note that the volcanic plume was best seen on the 7.3 µm images, which indicated that it began to move over the coast of Western Alaska after around 0600 UTC; this is due to the fact that the 7.3 µm band is not only a “water vapor absorption” band, but is also sensitive to high levels of SO2 loading in the atmosphere (as was pointed out in this blog post).

Himawari-8 AHI Water Vapor 7.3 µm (left), 6.9 µm (center) and 6.2 µm (right) images [click to play animation]

Himawari-8 AHI Water Vapor 7.3 µm (left), 6.9 µm (center) and 6.2 µm (right) images [click to play animation]