Fires continue in the southeast United States

November 14th, 2016

Terra MODIS (1650 UTC), Aqua MODIS (1829 UTC) and Suomi NPP VIIRS (1913 UTC) true-color images [click to enlarge]

Terra MODIS (1650 UTC), Aqua MODIS (1829 UTC) and Suomi NPP VIIRS (1913 UTC) true-color images [click to enlarge]

Fires (as seen on 07 and 10 November) continued to burn in parts of the southeast US on 14 November 2016. A sequence of 3 consecutive true-color Red/Green/Blue (RGB) images from Terra MODIS (1650 UTC), Aqua MODIS (1829 UTC) and Suomi NPP VIIRS (1913 UTC) viewed using RealEarth, above, showed the aerial extent of the dense smoke that was most concentrated over Tennessee, Georgia, North Carolina and South Carolina. With the aid of some of the 16 spectral bands on the ABI instrument aboard GOES-R, true-color images like these will be available at least once every 5 minutes over the Lower 48 states and adjacent areas.

GOES-13 (GOES-East) Visible (0.63 µm) images with plots of surface weather and visibility (below; also available as an MP4 animation) revealed that visibility was restricted to 3 miles or less at one or more sites in all of the aforementioned states. A pair of pilot reports in eastern Tennessee indicated that he top of the smoke layer was at 6000 feet above ground level.

GOES-13 Visible (0.63 µm) images, with hourly plots of surface weather (yellow) and visibility (statute miles, in cyan) [click to animate]

GOES-13 Visible (0.63 µm) images, with hourly plots of surface weather (yellow) and visibility (statute miles, in cyan) [click to animate]

High loading of particulate matter (PM) due to smoke led to AIRNow Air Quality Index ratings of Unhealthy (red)  to Very Unhealthy (purple) over much of that 4-state region (below).

Hourly AIRNow Particulate Matter (PM) Air Quality Index (AQI)

Hourly AIRNow Particulate Matter (PM) Air Quality Index (AQI)

===== 15 November Update =====

Suomi NPP VIIRS Shortwave Infrared (3.74 um) and Day/Night Band (0.7 um) images, plus METAR surface reports [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 um) and Day/Night Band (0.7 um) images, plus METAR surface reports [click to enlarge]

A toggle between Suomi NPP VIIRS Shortwave Infrared (3.74 um) and Day/Night Band (0.7 um) images (with and without METAR surface reports) at 0735 UTC or 3:35 am local time on 15 November (above) showed the “hot spot” signatures and bright glow from the larger fires that were burning in northern Georgia and western North Carolina. With ample illumination from the Moon — which was in the Waning Gibbous phase, at 99% of Full — smoke plumes from some of these fires could be seen drifting southward or southeastward,  thanks to the “visible image at night” capability of the Day/Night Band.

During the subsequent daytime hours, Terra MODIS and Suomi NPP VIIRS true-color RGB images (below) again revealed the vast coverage of the thick smoke — and VIIRS Aerosol Optical Depth values were quite high over South Carolina. Unhealthy AQI values persisted during much of the day across parts of Tennessee, Georgia and South Carolina.

Terra MODIS and Suomi NPP VIIRS true-color images, with VIIRS Aerosol Optical Depth (click to enlarge]

Terra MODIS and Suomi NPP VIIRS true-color images, with VIIRS Aerosol Optical Depth (click to enlarge]

A sampling of pilot reports (PIREPS) showed some of the impacts that the smoke was having on aviation (below).

Suomi NPP VIIRS Visible (0.64 µm) image with a PIREP over South Carolina [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) image with a PIREP over South Carolina [click to enlarge]

Aqua MODIS Visible (0.65 µm) image with a PIREP over Georgia [click to enlarge]

Aqua MODIS Visible (0.65 µm) image with a PIREP over Georgia [click to enlarge]

GOES-13 Visible (0.63 µm) image with a PIREP over North Carolina [click to enlarge]

GOES-13 Visible (0.63 µm) image with a PIREP over North Carolina [click to enlarge]

===== 16 November Update =====

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

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

Terra/Aqua MODIS and Suomi NPP VIIRS true-color images (above) showed that much of the smoke had moved over the adjacent offshore waters of the Atlantic Ocean on 16 November.

 

Halos due to the presence of ice crystal clouds

November 14th, 2016
Photo showing an Upper Tangent Arc, a Parhelia (Sun Dog), a Parhelic Circle segment and a faint 46 degree segment (upper right).

Photo showing an Upper Tangent Arc, a Parhelia (Sun Dog), a Parhelic Circle segment and a faint 46 degree segment (upper right).

Photos taken by SSEC scientist Claire Pettersen at 1615 UTC (above) and 1623 UTC (below) revealed several examples of ice crystal cloud optics over Madison, Wisconsin on 14 November 2016.  More information on the various types of ice cloud halos can be found here and here.

Photo showing a Circumzenithal Arc with a Supralateral Arc, in addition to an Upper Tangent Arc.

Photo showing a Circumzenithal Arc with a Supralateral Arc, in addition to an Upper Tangent Arc.

1650 UTC Terra MODIS Visible (0.65 µm), near-infrared Cirrus (1.375 µm) and Infrared Window (11.0 µm) images (below) showed the patches of cirrus clouds that were over southern Wisconsin not long after the photos above were taken. Many of the cirrus cloud features over the Madison (KMSN) area appeared very thin and nearly transparent on the Visible image; they also exhibited very warm Infrared Window brightness temperature values (warmer than -20ºC), since a great deal of radiation from the warmer surface of the Earth was reaching the MODIS detectors through the thin clouds. The 1.375 µm Cirrus band is able to detect the presence of airborne particles that are efficient scatterers of light — such as cirrus cloud ice crystals, dust, volcanic ash, smoke, haze — so the thin cirrus clouds exhibited a good signature on that image.

Terra MODIS Visible (0.65 µm), Cirrus (1.375 µm) and Infrared Window (11.0 µm) images [click to enlarge]

Terra MODIS Visible (0.65 µm), Cirrus (1.375 µm) and Infrared Window (11.0 µm) images [click to enlarge]

A similar 1.37 µm Cirrus Band will be on the ABI instrument aboard GOES-R.

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]

3-day transport of airborne Copper River Valley glacial silt/sand over the Gulf of Alaska

October 25th, 2016

GOES-15 Visible (0.63 µm) images, 23 through 25 October 2016, with hourly surface observations [click to play animation]

GOES-15 Visible (0.63 µm) images, 23 through 25 October 2016, with hourly surface observations [click to play animation]

GOES-15 (GOES-West) Visible (0.63 µm) images during the daylight hours on 23, 24 and 25 October 2016 (above) revealed the hazy signature of large amounts of airborne glacial silt and sand from the Copper River Valley being transported southward over the adjacent offshore waters of the Gulf of Alaska. The fine glacial silt and sand particles were being lofted by strong katabatic gap winds being channeled southward down the Copper River Valley — these winds were the result of a strong pressure gradient between arctic high pressure that was moving from the Interior of Alaska to the Yukon Territory of Canada (surface analyses) and a large occluded low centered off the coast of British Columbia and the US Pacific Northwest (24 October visible imagery).

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 24 October 2016 [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 24 October 2016 [click to enlarge]

Comparisons between Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 24 October (above) and 25 October (below) showed that the small airborne glacial silt/sand particles were very reflective to solar radiation, and exhibited a warmer (darker gray to black enhancement) signature in the Shortwave Infrared images (similar to the warmer signature seen due to spherical water droplets at the tops of supercooled stratiform clouds). On 25 October a large aerosol plume was also emerging from Yakutat Bay, moving southwestward.

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 25 October 2016 [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 25 October 2016 [click to enlarge]

Time series of surface observations at Middleton Island in the Gulf of Alaska [click to enlarge]

Time series of surface observations at Middleton Island in the Gulf of Alaska [click to enlarge]

A time series plot of surface observations from Middleton Island (PAMD) in the northern Gulf of Alaska (above) showed that the surface visibility was reduced to 3 miles on 24 October and 5 miles on 25 October as the Copper River plume periodically passed over the island. The ceiling height on 24 October was reported to be as low as 1400 feet as the surface visibility began to decrease. Along the southern coast of Alaska just west of the Copper River Delta, the visibility at Cordova (PACV) dropped to 5 miles with haze reported late in the day on 25 October as the western edge of the plume drifted over that area (below).

Time series of surface observations at Cordova, Alaska [click to enlarge]

Time series of surface observations at Cordova, Alaska [click to enlarge]

A zoom-in of the 2246 UTC Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image on 24 October (using RealEarth) showed the gray to light tan color of the glacial silt/sand plume.

Suomi NPP VIIRS true-color RGB images [click to enlarge]

Suomi NPP VIIRS true-color RGB images [click to enlarge]

Shown below are toggles between Suomi NPP VIIRS true-color RGB and Aerosol Optical Thickness (AOT) images (from the eIDEA site) for 23, 24 and 25 October. Very high values of AOT (in the 0.8 to 1.0 range) were associated with the Copper River plumes.

Suomi NPP VIIRS true-color RGB and Aerosol Optical Depth images for 23 October [click to enlarge]

Suomi NPP VIIRS true-color RGB and Aerosol Optical Depth images for 23 October [click to enlarge]

Suomi NPP VIIRS true-color RGB and Aerosol Optical Thickness images for 24 October [click to enlarge]

Suomi NPP VIIRS true-color RGB and Aerosol Optical Thickness images for 24 October [click to enlarge]

Suomi NPP VIIRS true-color RGB and Aerosol Optical Thickness images for 25 October [click to enlarge]

Suomi NPP VIIRS true-color RGB and Aerosol Optical Thickness images for 25 October [click to enlarge]

A toggle between Terra MODIS Visible (0.64 µm) and Infrared (11-12 µm, commonly referred to as the “split window difference”) Brightness Temperature Difference (BTD) images on 25 October (below) revealed that there was a very subtle Copper River plume signature in the BTD image (note: the default 11-12 µm BTD color enhancement was modified to better highlight the plume in this example).

Terra MODIS Visible (0.64 µm) and Infrared (11.0-12.0 µm) Brightness Temperature Difference images [click to enlarge]

Terra MODIS Visible (0.64 µm) and Infrared (11.0-12.0 µm) Brightness Temperature Difference images [click to enlarge]

In that respect, the MODIS Infrared “split window” BTD images could be used to help locate the Copper River plume during nighttime as well as daytime, as seen in the image comparison below. The ABI instrument on GOES-R will have similar 11 µm and 12 µm Infrared bands, and will have the capability to provide this type of BTD imagery at 5 minute intervals over the entire Full Disk scan.

Nighttime (0706 UTC) and daytime (2031 UTC) Terra MODIS Infrared (11-12 µm) Brightness Temperature Difference images [click to enlarge]

Nighttime (0706 UTC) and daytime (2031 UTC) Terra MODIS Infrared (11-12 µm) Brightness Temperature Difference images [click to enlarge]

Previous cases of similar airborne Copper River plumes have been documented on this blog: Oct 2014 | Nov 2013 | Oct 2012.