PyroCb

On 11 June 2015 there was pyroCb in Western Alberta (53.6 N 119.4 W) from a fire that started on 08 June. The start date of the fire was found from using the Canadian Wildland Fire Information System (link provided by Rene). The first image below shows active fires on 07 June. Notice that the area where the pyroCb was detected does not have an active fire on 07 June (area enclosed by red circle). By 08 June the same area (again enclosed by red circle) has an active fire greater than 1000 hectares. These images put the start date of the fire on 08 June.

Active Fires in Canada on 07 June

Active Fires in Canada on 08 June

Even though the fire started on 08 June it did not produce a pyroCb until 11 June around 23:00 UTC.GOES 15 detects the pyroCbs at visible (.63 μm) and IR (3.9 μm) channels shown below starting at 19:45 UTC 11 June (click in animation to play). In the IR image the red pixels indicate hot shortwave IR bright temperatures exhibited by the fire.

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

Furthermore, the cloud-top brightness temperature of the pyroCb can be found by using GOES-15 10.7 μm IR channel. In the image below, the coldest brightness temperature is -43.1ºC  around 23:30 UTC. This is indicated as a yellow pixels on the images. In addition, from Kelowna, BC and Stony Plain, Alberta sounds this puts the top of the pyroCB at 9.5 km.

GOES-15 10.7 μm IR image (click to animate)

The smoke plume is visible using Suomi NPP Land Surface True Color (below). The smoke plume is shown with as a brown color.

Suomi NPP True Color Image on 11 June (click to enlarge)

The image below shows the pyroCb that occurred in Grande Cache, AB around 22:40 Z (image courtesy by a colleague of Dov Bensimon). The image shows the depth of the pyroCb extending all the way up to the upper troposphere or possibly the lower stratosphere.

Image of the pyroCb (click to enlarge)

On 12 June OMPS AI Index images were used again to see the transport of the smoke. From the AI image (below; image courtesy of Colin Seftor), the smoke is moving northwest. On 12 June at 20:43 the max AI was at 58.44 N 119.29 W, which is just North of the original fire. The trajectory of this smoke can be seen using HYSPILT trajectory plot (courtesy of Mike Fromm). The plot at 10:00 UTC on 13 June shows a Northwestern trajectory that moves eastward then finally southwest. This conclusive with the AI image from the previous day that the smoke has moved northwest.

OMPS Aerosol Index images on 12 June (click to enlarge)

Backward Trajectory using HYSPLIT on 13 June (click to enlarge)

 To further investigate the transport of smoke from this fire CALIPSO was used, courtesy of Mark Fromm. This is a LIDAR that captures the attenuated backscatter at 532 nm. The image below shows the LIDAR from 13 June 9:45 UTC to 13 June 10:07 UTC. The pyroCb smoke can be seen ~51 N and indicated on the image with a light grey/white color. In addition, the CALIPSO Aerosol Subtype shows that these aerosols are smoke. This is shown in the image by the black pixels. These pixels are around 51N were the pyroCb smoke is suspected to be.

CALIPSO LIDAR image on 13 June (click to enlarge) 

CALIPSO Aerosol Subtype image on 13 June (click to enlarge)

Another look at CALIPSO LIDAR on 12 June produces additional information about the smoke transport. The first image below is the 532 nm Total Attenuated Backscatter plot on 12 June from 20:23 UTC to 20:37 UTC. The smoke from this fire is shown around 53 N indicated by a light grey/white color, continuing southeastward (toward the left on the plot). It is apparent that the source of the fire is around 53 N due to the smoke increasing in altitude as the LIDAR moves further southeast.  The next image is the Depolarization plot in which the smoke indicated by a red/pink color. The third image is 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 in this plot. The fifth image is the Vertical Feature Mask plot. This plot shows the different features that are in the atmosphere, in this plot the smoke is considered a cloud and 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 have detected are smoke (indicated by black pixels) around 54 N.

CALIPSO 532 nm Total Attenuated Backscatter on 12 June (click to enlarge)

CALIPSO Depolarization Ration on 12 June (click to enlarge)

CALIPSO 1064 nm Total Attenuated Backscatter on 12 June (click to enlarge)

CALIPSO Attenuated Color Ratio between 1064 nm and 532 nm on 12 June (click to enlarge image)

CALIPSO Vertical Feature Mask on 12 June (click to enlarge image)

CALIPSO Aerosol Subtype plot on 12 June (click to enlarge image)

A fire in northern Alberta (58.6W 113.4N) on 5 June 2015 produced two pyroCbs. This is a fire is the same that was investigated for possibly producing pyroCbs on 3 June 2015. However, on the 3 June fire there ended up not being any pyroCbs. The first pyroCb started around 23:00 UTC on 5 June, and the second starting at 02:15 UTC on 6 June. GOES 15 detects the pyroCbs at visible (.63 μm) and IR (3.9 μm) channels shown below starting at 00:00 UTC 6 June (click in animation to play). In the IR image the red pixels indicate hot shortwave IR bright temperatures exhibited by the fire.

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

The GOES-15 10.7 μm IR channel image below shows the pyroCb cloud-top brightness temperatures. The first pyroCb is seen with the coldest brightness temperature at -43.5°C at 00:30 UTC indicated by the lime green color. The second pyroCb at a temperature of -47.9°C around 03:30 UTC indicated by the lime green color.

GOES-15 10.7 μm IR image (click to animate)

Later on in the day another pyroCb formed from the same fire at 22:00 UTC 6 June 2015.GOES 15 detects the pyroCbs at visible (.63 μm) and IR (3.9 μm) channels shown below starting at 00:00 UTC 6 June (click in animation to play). In the IR image the red pixels indicate hot shortwave IR bright temperatures exhibited by the fire.

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

The GOES-15 10.7 μm IR channel image below shows the pyroCb cloud-top brightness temperature. For this pyroCb the coldest brightness temperature was -47.2ºC. This is indicated on the animation with a lime green color.

GOES-15 10.7 μm IR image (click to animate)

The image below shows the smoke plume from the fire indicated by a brown/grey color. From the image it can be seen that the smoke plume is moving southeast.

Suomi NPP True Color Image on 6 June (click to enlarge)

Smoke transport from this fire in Alberta can be followed using the OMPS Aerosol Index (AI) product. The following images are comparisons of AI images from consecutive satellite overpasses on 6 June and 7 June (images courtesy of Colin Seftor). On 6 June there is an eastward transport of the smoke while on 7 june there is a southeastward transport.

OMPS Aerosol Index images on 6 June (click to enlarge)

OMPS Aerosol Index images on 7 June (click to enlarge)

To further investigate the transport of smoke from this fire CALIPSO was used, courtesy of Mark Fromm. This is a LIDAR that captures the attenuated backscatter at 532 nm. The image below shows the LIDAR from 08 June 7:52 UTC to 08 June 8:15 UTC. The pyroCb smoke can be seen ~55 N and indicated on the image with a red color. Furthermore, it is also shown under the smoke that the troposphere bends putting the smoke in the stratosphere.

CALIPSO LIDAR image on 8 June (click to enlarge)

In addition, looking again at CALIPSO LIDAR images from 06 June. The first image below is 532 nm Total Attenuated Backscatter plot on 06 June form 19:21 UTC to 19:35 UTC. The smoke can be seen starting around 40 N extending to 51 N indicated by light grey color. The next image is the Depolarization image the smoke is indicated by a red/pink color. The third image is 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 the teal and purple pixels. The final 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.

CALIPSO 532 nm Total Attenuated Backscatter on 06 June (click to enlarge)

CALIPSO Depolarization Ration on 06 June (click to enlarge)

CALIPSO 1064 nm Total Attenuated Backscatter on 06 June (click to enlarge)

CALIPSO Attenuated Color Ratio between 1064 nm and 532 nm on 06 June (click to enlarge image)

CALIPSO Vertical Feature Mask on 06 June (click to enlarge image)

Furthermore, HYSPLIT trajectory plot (courtesy of Rene) was used to find the backward trajectory of the smoke that was found at 55 N 82W. The fire that was originally at 58.6W 113.4N and is seen closely following the red trajectory line. From this trajectory line it is seen that the smoke is see at 55 N 82W, which are the coordinates found from the LIDAR. This confirms our hypothesis that the smoke cloud found on the LIDAR was from this fire in Alberta.

Backward Trajectory using HYSPLIT on 8 June

By 09 June the smoke had reached the northern parts of the United States. The OMPS Aerosol Index (AI) product shows the smoke transport into the upper Midwest states later in the day on 08 June. The image below shows comparisons of AI images from consecutive satellite overpasses (images courtesy of Colin Seftor).

OMPS Aerosol Index images on 8 June (click to enlarge)

The GOES-13 visible channel animation below starts at 11:00 UTC on 09 June and shows the smoke transport into the upper Midwest. The trajectory of this smoke is consistent with the AI images above. Even though the AI images are on 08 June and the visible animation is on 09 June, it can be deduced from the AI images that the trajectory of the smoke is what is pictured in the animation.

GOES-13 visible image (click to enlarge)

A fire in Northern Alberta (58 N, 113 W) began showing signs of becoming a PyroCb late in the date on 3 June 2015 into the morning of 4 June. This fire is among the 39 wildfire currently burning in the region, spurring a providence wide fire ban. GOES 15 detected this occurrence at visible (.63 μm) and IR (3.9 μm) channels shown below (below; click in animation to play).

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

However, from the IR image at 10.7 μm (below; click in animation to play) there is no sign of clouds that have developed enough. The clouds produced from this wildfire did not grow enough in the atmosphere to acquire a brightness temperature less than -40⁰C which is indicative of a PyroCb.

GOES-15 10.7 μm IR image (click to animate)

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

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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.

CALIPSO 532 nm Total Attenuated Backscatter on 30 May (click to enlarge)

CALIPSO Depolarization Ration on 30 May (click to enlarge)

CALIPSO 1064 nm Total Attenuated Backscatter on 30 May (click to enlarge)

CALIPSO Attenuated Color Ratio between 1064 nm and 532 nm on 30 May (click to enlarge image)

CALIPSO Vertical Feature Mask on 30 May (click to enlarge image)

CALIPSO Aerosol Subtype plot on 30 May (click to enlarge image)