Multiple pyroCb events in Canada’s Northwest Territories

Suomi NPP VIIRS 0.64 µm visible, 3.74 µm shortwave IR, and 11.45 µm IR images

A comparison of 375-meter resolution Suomi NPP VIIRS 0.64 µm visible, 3.74 µm shortwave IR, and 11.45 µm IR images at 2125 UTC on 30 May 2015 (above) showed widespread smoke plumes and “hot spots” (yellow to red to black enhancement) from wildfires that were burning across far western portions of Canada’s Northwest Territories and adjacent areas of northern British Columbia and Alberta. The surface observations showed that a warm and dry air mass was in place across the region, in advance of an arctic cold front approaching from the northwest; this warm, dry air was being drawn northward by a low centered farther to the south over southern British Columbia (GOES-15 visible/shortwave IR animation).

The numerous smoke plumes were also very apparent on Aqua MODIS and Suomi NPP VIIRS true-color images (below).

Aqua MODIS and Suomi NPP VIIRS true-color images

—————————————————————————————–

GOES-15 0.63 µm visible (left) and 3.9 µm shortwave IR (right) images (click to play animation)

GOES-15 (GOES-West) 0.63 µm visible channel and 3.9 µm shortwave IR channel images (above; click image to play animation; also available as an MP4 movie file) showed the temporal evolution of the fire hot spots (dark black to red color enhancement) as well as the development of pyroCb clouds from some of the larger, hotter fires. It appears that an unusually high number of 5 separate pyroCb clouds resulted from this single outbreak of fires.

The corresponding GOES-15 10.7 µm IR channel images (below; click image to play animation; also available as an MP4 movie file) revealed the pyroCb clouds whose cloud-top IR brightness temperature became colder than -40º C (darker green color enhancement). By the end of the animation, large parts of the pyroCb anvils exhibited IR brightness temperatures around -60º C (darker red color enhancement) as they drifted eastward.

GOES-15 10.7 µm IR images (click to play animation)

Smoke transport from these Northwest Territories fires could followed using the OMPS Aerosol Index (AI) product — comparisons of AI images from consecutive satellite overpasses on 30 May, 31 May, and 01 June (below; images courtesy of Colin Seftor) showed a southeastward transport of smoke that was over James Bay by 01 June.

OMPS Aerosol Index images on 30 May

OMPS Aerosol Index images on 31 May

OMPS Aerosol Index images on 01 June

To further investigate the transport of smoke from these fires CALIPSO LIDAR was used. This LIDAR shows the height of the clouds produced from these wildfires. The first image is the 532 nm Total Attenuated Backscatter plot on 30 May from 11:14 UTC to 11:26 UTC. The smoke from these fires can be seen extending from 61 N to 68 N indicated by light grey pixels. This furthermore confirms that the smoke is moving northeast because the height of the smoke increase as the latitude increases and the longitude decreases. The next image is the Depolarization plot, on this plot the smoke is indicated by a red/pink color. The third image is the 1064 nm Total Attenuated Backscatter plot, the smoke on this plot is indicated by a light grey color. The fourth image is the Attenuated Ratio plot between 1064 nm and 532 nm. The smoke is indicated by teal and purple pixels. The fifth image is the Vertical Feature Mask. This plot shows the different features that are in the atmosphere, the smoke is attributed as a cloud on this plot and is indicated by a light blue color. The last image shows the subtype of the aerosols that have been detected by the LIDAR. This shows that the aerosols that the LIDAR has detected are smoke (indicated by black pixels) around 62 N.