CIMSSPyroCb

Stouts Fire in Oregon

GOES-15 0.63 µm visible channel (left) and 3.9 µm shortwave IR channel images (right)  [click to play animation]
GOES-15 0.63 µm visible channel (left) and 3.9 µm shortwave IR channel images (right) [click to play animation]
GOES-15 (GOES-West) 0.63 µm visible channel and 3.9 µm shortwave IR channel images (above; click to play animation; also available as an MP4 movie file) showed that the Stouts Fire (InciWeb | Wildfire Today) began to rapidly intensify in southwestern Oregon around 2030 UTC (1:30 pm local time) on 30 July 2015.

GOES-15 10.7 µm IR images (below; click image to play animation; also available as an MP4 movie file) indicated that the cloud-top IR brightness temperature (BT) became colder than -40º C (bright green color enhancement) after about 0100 UTC on 31 July, becoming the first verified pyroCb in the Lower 48 States for the 2015 wildfire season. The IR BT continued to cool to around -50º C (yellow color enhancement) after 0200 UTC.

GOES-15 10.7 µm IR channel images [click to play animation]
GOES-15 10.7 µm IR channel images [click to play animation]
A NOAA-18 AVHRR image at 0139 UTC (below; courtesy of Rene Servranckx) indicated that the minimum IR BT was -56.1º C, which corresponded to an altitude of approximately 12.2 km based on the 31 July / 00 UTC Medford, Oregon rawinsonde. This altitude was just below the tropopause (which was defined on the sounding data to be at 12.6 km); winds at that level were southwesterly around 40 knots.

NOAA-18 AVHRR 0.63 µm visible (upper left), 3.7 µm shortwave IR (upper right), 10.8 µm IR (lower left), and false-color RGB image (lower right) [click to enlarge]
NOAA-18 AVHRR 0.63 µm visible (upper left), 3.7 µm shortwave IR (upper right), 10.8 µm IR (lower left), and false-color RGB image (lower right) [click to enlarge]
During the 0230-0300 UTC time period, there were 4 negative-polarity cloud-to-ground lightning strikes recorded beneath the Stouts Fire pyroCb cloud (below; courtesy of Nick Nauslar).

Cloud-to-ground lightning strikes (0230-0300 UTC)
Cloud-to-ground lightning strikes (0230-0300 UTC)

The fire continued to burn well into the nighttime hours; on a comparison of Suomi NPP VIIRS images at 1028 UTC or 3:28 am local time (below), an intense fire hot spot was evident on the 3.74 µm shortwave IR image (yellow to red to black color enhancement) which also showed up as a brightly glowing feature on the 0.8 µm Day/Night Band image. Because of ample illumination from a Full Moon, the Day/Night Band provided a “visible image at night” which enabled the leading edge of the pyroCb smoke to be seen spreading over northeastern Oregon, far southeastern Washington, and northern Idaho. The coldest VIIRS IR BT at that time was -50º C over northeastern Oregon.

Suomi NPP VIIRS 3.74 µµ shortwave IR, 0.8 µm Day/Night Band, and 11.45 µm IR images [click to enlarge]
Suomi NPP VIIRS 3.74 µµ shortwave IR, 0.8 µm Day/Night Band, and 11.45 µm IR images [click to enlarge]
On the following day (31 July), successive Suomi NPP VIIRS true-color images (below) showed that the leading edge of the Stouts Fire smoke was over eastern Montana at 1832 UTC, and over southwestern North Dakota at 2013 UTC.

Suomi NPP VIIRS true-color image at 1832 UTC on 31 July [click to enlarge]
Suomi NPP VIIRS true-color image at 1832 UTC on 31 July [click to enlarge]
Suomi NPP VIIRS true-color image at 2013 UTC on 31 July [click to enlarge]
Suomi NPP VIIRS true-color image at 2013 UTC on 31 July [click to enlarge]
This smoke transport was consistent with forward trajectories calculated using the HYSPLIT model (below).

HYSPLIT forward trajectories [click to enlarge]
HYSPLIT forward trajectories [click to enlarge]
On 31 July, Suomi NPP OMPS Aerosol Index values (below; courtesy of Colin Seftor) were as high as 5.4 over far southwestern North Dakota.

Suomi NPP OMPS Aerosol Index on 31 July [click to enlarge]
Suomi NPP OMPS Aerosol Index on 31 July [click to enlarge]

PyroCb in Russia

On 29 July there was a possibility of a pyroCb forming just east of Lake Baikal in Russia. From Himwari-8 images it was confirmed that a pyroCb formed around 53 N 109 E. Himawari-8 detected the smoke plume and clouds around the fires, as well as the fire hot spots. Starting at 07:00 UTC on 29 July, the animation below shows visible (.64 μm) on the left and shortwave IR (3.9 μm) on the right (click image to play animation). In the shortwave IR images the darker black to red pixels indicate very hot IR brightness temperatures exhibited by the fire source region.

Himawari-8 0.64 μm visible (left) and 3.9 μm shortwave IR (right) images [click to play animation]
Himawari-8 0.64 μm visible (left) and 3.9 μm shortwave IR (right) images [click to play animation]
 In addition, using Himawari-8 10.4 μm IR channel imagery the minimum cloud-top IR brightness temperatures could be found. The animation below, starting at 07:00 UTC on 29 July, shows that the possbile pyroCb reached around -40ºC (lime green color enhancement) at 10:20 UTC.

Himawari-8 10.4 μm IR images (click to play animation)
Himawari-8 10.4 μm IR images (click to play animation)

OMPS AI index image (courtesy of Colin Seftor) shows the transport of smoke. The image on 30 July shows a high AI values around the area of the pyroCb. However, this image is detecting the smoke from the multiple fires in the area and not the fire that produced the pyroCb specifically.

OMPS Aerosol Index image on 30 July (click to enlarge)
OMPS Aerosol Index image on 30 July (click to enlarge)

Furthermore, the image of the Biomass Burning Aerosol Optical Depth at 550 nm (image courtesy of Mark Parrington) shows how much smoke concentration that is an area. There is a high optical depth in Russia from these multiple wild fires. The bulk of this smoke is moving East and possibly reaching the west coast of North America in a few days.

Biomass Burning Aerosols Optical Depth at 550 nm (click to enlarge)
Biomass Burning Aerosols Optical Depth at 550 nm (click to enlarge)

Wildfire Smoke over Asia

Note: even though this large-scale smoke event was not pyroCb-related, we feel that it is important enough to document in terms of the long-range transport of biomass burning smoke and the potential implications on weather and climate far from the fire source regions.

Himawari-8 Visible imagery (click to animate)
Himawari-8 Visible imagery (click to animate)

Himawari-8 shows the smoke over the northeastern part of Asia. The animation above (from 22:00 UTC on 18 July to 06:00 UTC on 19 July) shows smoke moving off the eastern side of Asia, the smoke is indicated as a hazy white color. Furthermore, closely looking at the animation smoke plumes can be seen from the multiple wildfires. Also, the smoke does not seem to be moving very quickly and its shape possible indicating that it is following the path of a jet stream.

OMPS AI Index image on 19 July (courtesy of Colin Seftor) shows the transport of the smoke from these wildfires. The max AI was 5.9 at 55.5 N 126.9 E, the max value is northeast of the area where most of the wildfires are concentrated.

OMPS AI Index on 19 July (click to enlarge)
OMPS AI Index on 19 July (click to enlarge)

Furthermore, Suomi NPP VIIRS true-color imagery shows the progression of the smoke. The animation starts on 10 July where there appears to be little smoke. By 19 July most of the area is covered in hazy smoke. Also, looking closely at the animation smoke plumes can be seen and areas where the wildfires are orginating from.

Suomi NPP VIIRS (click to animate)
Suomi NPP VIIRS (click to animate)

Furthermore, looking at the CO mixing ratio this provides information on how much carbon monoxide is in the atmophere. The higher the CO amount, the higher the mixing ratio, and which means areas of dense smoke. The image below shows the CO mixing ratio on 19 July (courtesy of Leonid Yurganov). The are under investigation has a CO mixing ratio of 220 ppbv (indicated by dark red) , which is rather high thus there must be a lot of smoke in the area.

CO Mixing Ratio on 19 July (click to enlarge)
CO Mixing Ratio on 19 July (click to enlarge)

Wildfire smoke: from Alaska to Norway, via the Arctic and Atlantic Oceans

Note: even though this large-scale smoke event was not pyroCb-related, we feel that it is important enough to document in terms of the long-range transport of biomass burning smoke and the potential implications on weather and climate far from the fire source regions.

Meteosat-10 0.8 µm visible channel images [click to play animation]
Meteosat-10 0.8 µm visible channel images [click to play animation]
EUMETSAT Meteosat-10 High Resolution Visible (0.8 µm) images (above; click to play animation; also available as an MP4 movie file) revealed the hazy signature of what appeared to be a ribbon of smoke aloft being transported eastward across the North Atlantic Ocean by the circulation of a large area of low pressure (surface | 500 hPa) on 17 July 2015. Early in the day, the smoke feature stretched from the east coast of Greenland to the central Atlantic Ocean; by the end of the day, the leading edge of the smoke had moved over the British Isles and was headed toward Scandinavia.

A portion of the smoke plume could be seen on Aqua MODIS and Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images (below) as it was approaching the southern portion of Great Britain.

Aqua MODIS and Suomi NPP VIIRS true-color images [click to enlarge]
Aqua MODIS and Suomi NPP VIIRS true-color images [click to enlarge]
On the following morning, Meteosat-10 visible images (below; click to play animation) showed that the leading edge of the smoke ribbon was moving over southern Norway.

Meteosat-10 0.8 µm visible channel images [click to play animation]
Meteosat-10 0.8 µm visible channel images [click to play animation]
The transport pathway of this smoke feature was rather interesting, as we shall explore with the following sets of images.

Suomi NPP VIIIRS 3.74 µm shortwave IR and 0.64 µm visible images on 06 July [click to enlarge]
Suomi NPP VIIIRS 3.74 µm shortwave IR and 0.64 µm visible images on 06 July [click to enlarge]
The 2015 wildfire season in Alaska had been very active — as of 17 July, it was rated as the 4th worst in terms of total acreage burned. In early July, numerous wildfires burning across the interior of Alaska were producing a large amount of smoke, as can be seen in a comparison of of Suomi NPP VIIRS 3.74 µm shortwave IR and 0.64 µm visible channel images at 2131 and 2312 UTC on 06 July (above). The thermal signature of the wildfire “hot spots” showed up as yellow to red to black pixels on the 2 shortwave IR images, while the widespread smoke plumes from the fires are evident on the 2 visible images; even in the relatively short 101 minutes separating the two sets of VIIRS images, notable changes in fire activity could be seen.

Looking a bit farther to the north and west, a sequence of VIIRS 0.64 µm visible images centered over Cape Lisburne (station identifier PALU) in northwestern Alaska covering a 2-day period from 06 to 08 July (below) showed the initial transport of large amounts of smoke from the interior of Alaska northwestward over the Chukchi Sea between Alaska and Russia.

Suomi NPP VIIRS 0.64 µm visible channel images covering the 06-08 July period [click to enlarge]
Suomi NPP VIIRS 0.64 µm visible channel images covering the 06-08 July period [click to enlarge]
Daily composites of Suomi NPP OMPS Aerosol Index covering the period of 04-17 July (below; courtesy of Colin Seftor; see his OMPS Blog post) showed the strong signal of this dense Alaskan smoke (denoted by the red arrows) as it moved from east to west over the far southern Arctic Ocean and along the far northern coast of Russia from 06-10 July. The Aerosol Index signal seemed to stall north of Scandinavia on 12-13 July, but then a small portion began to move toward Iceland and Greenland on 13-15 July around the periphery of a large upper-level low (500 hPa analyses). Finally, some of this smoke was then transported eastward across the Atlantic Ocean around the southern periphery of this upper-level low on 17 July, as was seen on the Meteosat-10 visible images at the beginning of this blog post.

Suomi NPP OMPS Aerosol Index images, covering the period 04-17 July [click to enlarge]
Suomi NPP OMPS Aerosol Index images, covering the period 04-17 July [click to enlarge]
CALIOP lidar data from the CALIPSO satellite (below) showed the vertical distribution of the Alaskan smoke over and off the coast of northern Norway on 11 July. The signal of the smoke was located in the center portion of the images; while there appeared to be some smoke at various altitudes within the middle to upper troposphere, a significant amount of smoke was seen in the lower stratosphere in the 10-12 km altitude range.

CALIPSO CALIOP lidar data showing the smoke over northern Norway on 11 July [click to enlarge]
CALIPSO CALIOP lidar data showing the smoke over northern Norway on 11 July [click to enlarge]

Possible PyroCb in Southeast Russia

On 12 July there was a possibility for pyroCb development in southeast Russia. By using satellite imagery from the new Japanese satellite Himawari-8 it was confirmed that these clouds formed near the fires but were not technically pyroCb. Himawari-8 detected the smoke plume and clouds around the fires, as well as the fire hot spots. Starting at 04:00 UTC on 12 July, the animation below shows visible (.64 μm) on the left and shortwave IR (3.9 μm) on the right (click image to play animation). In the shortwave IR images the darker black to red pixels indicate very hot IR brightness temperatures exhibited by the fire source region.

Himawari-8 0.64 μm visible (left) and 3.9 μm shortwave IR (right) images [click to play animation]
Himawari-8 0.64 μm visible (left) and 3.9 μm shortwave IR (right) images [click to play animation]
In addition, using Himawari-8 10.4 μm IR channel imagery the minimum cloud-top IR brightness temperatures could be found. The animation below, starting at 04:00 UTC on 12 July, shows that the possbile pyroCb reached around  -55ºC (red color enhancement) at 8:00 UTC.

Himawari-8 10.4 μm IR images (click to play animation)
Himawari-8 10.4 μm IR images (click to play animation)

OMPS AI index image (courtesy of Colin Seftor) shows the transport of smoke. The image on 13 July shows a high AI value south of the fires discussed above. This is consistent with the animations above of a southward transport of this smoke.

OMPS Aerosol Index image on 13 July (click to enlarge)
OMPS Aerosol Index image on 13 July (click to enlarge)

Also looking at the CO mixing ratio image on 15 July (below, courtesy of Leonid Yurganov) shows a very high mixing ratio near the area where the possible pyroCb took place. According to the image the area around the wildfires has a CO mixing ratio of 220 ppbv (indicated by a dark red color), which is a very high mixing ratio.

CO Mixing Ratio on 15 July (click to enlarge)
CO Mixing Ratio on 15 July (click to enlarge)

Looking from above these smoke plumes are quite magnificent. The images (courtesy of Klaus) were taken approximately at 54 N 127 E at 08:00 UTC on 14 July. From the images the smoke plumes to be extending far up into the troposphere, possibly even parts of the lower stratosphere.

Smoke plumes in Asia on 14 July (click to enlarge)
Smoke plumes in Asia on 14 July (click to enlarge)
Smoke plumes in Asia on 14 July (click to enlarge)
Smoke plumes in Asia on 14 July (click to enlarge)

Smoke over North America

In Canada and Alaska, 2015 has been the year for wildfires. As of 08 July, the number of acres burned in Alaska has been the second highest in recorded history. In Canada the acres burned already exceeds the annual 10-year average for an entire year (image below). The government has deployed 1,000 military personnel to help fight wildfires in Saskatchewan (information and image provided by Wildfire Today).

Canada are burned on a weekly basis through week of July 1, 2015 (click to enlarge)
Canada are burned on a weekly basis through week of July 1, 2015 (click to enlarge)

As of 08 July the United States has had 30,017 fires burning 3,821,726 acres, Alaska has had 650 fires burning 3,208,107 acres, and Canada has had 4,672 fires burning 6,546,562 acres. The images below show the fire activity for Canada and Alaska at 2:45 UTC on 09 July (courtesy of Wildfire Today).

Canada Fires at 02:45 UTC on 09 July (click to enlarge)
Canada Fires at 02:45 UTC on 09 July (click to enlarge)
Alaska Fires at 02:45 UTC on 09 July (click to enlarge)
Alaska Fires at 02:45 UTC on 09 July (click to enlarge)

From these wildfires, massive amounts of smoke have been produced. This smokes has been covering parts of Canada and the United States for most of the summer. OMPS Aerosol Index (AI) helps show the transport of this smoke. Below is the image of the OMPS AI on 04 July (courtesy of Colin Seftor and information from Rene). On this image are three different areas with very high AI values. The first area is around the Great Lakes at 47.72 N 88.3 W with an AI value of 14.3 at 18:46 UTC. This cluster was produce by numerous fires in Saskatcehwan. This smoke could possibly be from the three pyroCbs that produced at 21:00 UTC on 03 July. Farther north the next area at 52.27 N 92.5 W had an AI value of 16.6 at 18:48 UTC. This cluster again is most likely from the pyroCbs in Saskatachewan. The last cluster to the west at 53.84 N 106.07 W produced an AI value of 11.1 at 18:48 UTC. This cluster came from the fires in northern Alberta.

OMPS Aerosol Index image on 04 July (click to enlarge)
OMPS Aerosol Index image on 04 July (click to enlarge)

On 06 July the OMPS AI index image (courtesy of Colin Seftor) provides information about the smoke transport since 04 July. There are two areas of very high AI values. The first that covers part of Washington and Montana is from a fire in British Columbia that produced a pyroCb on 05 July. The other are of very high AI value is in the center of Canada. This value is from the multiple fires in Saskatchewan, some even producing pyroCbs.

OMPS Aerosol Index image on 06 July (click to enlarge)
OMPS Aerosol Index image on 06 July (click to enlarge)

The OMPS AI index images (courtesy of Colin Seftor) on 07 July show the transport of smoke across Canada and into the North Pole. The first image shows high AI values from fires in Saskatchewan and British Columbia. There are high AI values in Montana and North Dakota from the fires in British Columbia. The second image shows high AI values from fires in Alaska. This smoke is not moving east like it usually does, but is moving northwest into the North Pole.

OMPS Aerosol Index image on 07 July (click to enlarge)
OMPS Aerosol Index image on 07 July (click to enlarge)
OMPS Aerosol Index image on 07 July (click to enlarge)
OMPS Aerosol Index image on 07 July (click to enlarge)

Furthermore, the northwestward drift of the smoke from Alaska can be seen using VIIRS visible imagery.

Suomi NPP VIIRS True-Color visible image of Alaska Smoke o 07 July (click to animate)
Suomi NPP VIIRS True-Color visible image of Alaska Smoke o 07 July (click to animate)

On 08 July the OMPS AI index image (courtesy of Colin Seftor) showed the AI index in the shape of a wishbone. These high values of AI came from fires in Alberta and Saskatchewan. Furthermore, Suomi NPP VIIRS true-color visible, shortwave IR, and IR images showed the smoke adding a  light brown hue to the convective clouds. This visible image correlates nicely with the high AI values shown in the first image. Also, the visible image shows smoke plumes originating form a cluster of hot spots just east of the Yukon/Northwest Territories.  In addition, from the IR image the coldest cloud-top brightness temperatures were between -59ºC to -60ºC.

OMPS Aerosol Index image on 08 July (click to enlarge)
OMPS Aerosol Index image on 08 July (click to enlarge)
Suomi NPP VIIRS visible, shortwave IR, and IR at 20:54 UTC on 08 July (click to animate)
Suomi NPP VIIRS visible, shortwave IR, and IR at 20:54 UTC on 08 July (click to animate)

By 09 July the max AI values were in the northern part of the United States. OMPS AI index images (courtesy of Colin Seftor) show a band of smoke extending the northern part of the United States. This smoke is coming from fires in British Columbia, possibly from a fire that produced a pyroCb a few days later.

OMPS Aerosol Index image on 09 July (click to enlarge)
OMPS Aerosol Index image on 09 July (click to enlarge)
OMPS Aerosol Index image on 09 July (click to enlarge)
OMPS Aerosol Index image on 09 July (click to enlarge)

This smoke has provided some interesting features on visible and water vapor imagery. The images below show visible and water vapor imagery on 09 July at 17:45 UTC (courtesy of Darren Clabo). These images show this smoke band extending from Montana to the middle of Minnesota.

Visible imagery on 09 July (click to enlarge)
Visible imagery on 09 July (click to enlarge)
Water vapor imagery on 09 July (click to enlarge)
Water vapor imagery on 09 July (click to enlarge)

Furthermore, this air seems to be trapped with a ribbon of very dry air associated with lowering of the dynamic tropopause. The reason the tropopause is lowering is due to a potential vorticity anomaly moving eastward across Minnesota. Furthermore, with this smoke being trapped in dry air it is common for it to cause stratospheric intrusions. By looking at the Total Column Ozone (shown in the image below) there are higher values in the ribbon of dry air. This is conclusive with the hypothesis that there are some stratospheric intrusions within this ribbon of dry air.

Total Column Ozone on 09 July (click to enlarge)
Total Column Ozone on 09 July (click to enlarge)

In addition, there are two vortices over Montana. The image below tweeted by the NWS office in Glasgow, MT shows the vortices. In addition, the GOES visible imagery below shows the two vortices on 10 July starting at 11:30 UTC.

Visible image over Montana on 10 July (click to enlarge)
Visible image over Montana on 10 July (click to enlarge)
GOES-15 visible imagery on 10 July (click to play animation)
GOES-15 visible imagery on 10 July (click to play animation)

On 10 July the OMPS AI index image (courtesy of Colin Seftor) showed the smoke that was in the northern part of the United States on 09 July moving east and off to the eastern coast.

OMPS Aerosol Index image on 10 July (click to enlarge)
OMPS Aerosol Index image on 10 July (click to enlarge)