PyroCb near Perth in Western Australia

Himawari-8 Shortwave Infrared (3.9 µm, left) and Visible (0.64 µm, right) images [click to play animation]

Himawari-8 Shortwave Infrared (3.9 µm, left) and Visible (0.64 µm, right) images [click to play animation]

A 2-panel comparison of Himawari-8 Shortwave Infrared (3.9 µm) and Visible (0.64 µm) images (above) showed the “hot spot” (red pixels) associated with a large bush fire burning near Waroona (south of Perth) in Western Australia on 06 January 2016 (media report), along with smoke from the fire and the explosive development of a pyroCb cloud after about 0830 UTC. The variation in smoke transport was explained by the strong vertical wind shear profile seen on a plot of 12 UTC Perth rawinsonde data: easterly winds within the 800m-2000m layer were carrying smoke westward off the coast, while smoke transported to higher altitudes by the pyroCb cloud was drifting southeastward due to northwesterly flow aloft.

Himiwari-8 Infrared (10.4 µm) images (below) indicated that cloud-top IR brightness temperatures cooled to -40º C (bright green color enhancement) around 0830 UTC, eventually reaching a minimum of -56º C (darker orange color enhancement). According to analysis performed by René Servranckx, the coldest cloud-top IR brightness temperature detected by the AVHRR instrument on NOAA-18 was -61.2º C at 1104 UTC (which corresponds to an altitude of 14 km based upon the Perth rawinsonde data).

Himawari-8 Infrared (10.4 µm) images [click to play animation]

Himawari-8 Infrared (10.4 µm) images [click to play animation]

During the nighttime hours following the initial pyroCb development, the fire raced westward as revealed by the spreading out of the red pixels on Himawari-8 Shortwave IR (3.9 µm) images and the light gray to brighter white pixels on Near-IR (2.3 µm) images (below).

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

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

Himawari-8 Near-IR (2.3 µm) images [click to play animation]

Himawari-8 Near-IR (2.3 µm) images [click to play animation]

On 07 January, two additional pyroCb clouds were seen to develop from the Waroona fire: the first after about 03 UTC, and the second after about 06 UTC. In this case, the pyroCb cloud material was transported rapidly eastward, as seen in Himawari-8 Infrared (10.4 µm) images (below), due to an increase in westerly winds aloft as seen in a plot of 00 UTC Perth rawinsonde data. An animation of Himawari-8 true-color images showing these 2 pyroCb events can be seen here.

Himawari-8 Infrared (10.4 µm) images [click to play animation]

Himawari-8 Infrared (10.4 µm) images [click to play animation]

A comparison of Suomi NPP VIIRS true-color images from 06 January and 07 January (below) showed an increase in the thickness and areal coverage of smoke aloft over the region (Note: the actual overpass times of the Suomi NPP satellite were between 06 and 07 UTC, as seen here and here). A plot of VIIRS-detected fire locations (red dots) for the period ending at 12 UTC on 07 January is also shown.

Suomi NPP VIIRS true-color images from 06 January and 07 January [click image to enlarge]

Suomi NPP VIIRS true-color images from 06 January and 07 January [click image to enlarge]

To further investigate the transport of smoke from this fire CALIPSO was used. This LIDAR shows the height of the clouds from the wildfire. The first image below is the 532nm Total Attenuated Backscatter plot on 07 January from 05:37 UTC to 6:00 UTC. The smoke from this fires can be seen ~ 32 S indicated faintly by a red/grey color. The second image is 1064 nm Total Attenuated Backscatter plot, the smoke on this plot is indicated by a grey color. The third image is the Depolarization image the smoke is indicated by a red color. The fourth image is the Attenuated Ratio plot between 1064 nm and 532 nm. The smoke is indicated by the light blue 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.
2016-01-07_04-30-00_Exp_V3.30_4_1CALIPSO 532 nm Total Attenuated Backscatter on 07 January (click to enlarge)

2016-01-07_04-30-00_Exp_V3.30_4_4CALIPSO 1064 nm Total Attenuated Backscatter on 07 January (click to enlarge)

2016-01-07_04-30-00_Exp_V3.30_4_3CALIPSO Depolarization Ration on 07 January (click to enlarge)

2016-01-07_04-30-00_Exp_V3.30_4_5CALIPSO Attenuated Color Ratio between 1064 nm and 532 nm on 07 January (click to enlarge image)

2016-01-07_04-30-00_Exp_V3.30_4_6CALIPSO Vertical Feature Mask on 07 January (click to enlarge image)

Below is an animation of the convergence at 250 mb shown by a color fill, the the 250 mb geopotential height contoured every 30 meters and the wind barbs.It has been investigated that upper level divergence is associated with the ability for pyroCu to turn into a pyroCb (Peterson et al., BAMS, Feb. 2015, 229-247). Starting at 0 UTC on 06 January the spot of the pyroCbs are indicated by the white dots. These pyroCbs are in an area of divergence indicated by the light blue and dark green color. This is conducive to the strengthening of the pyroCb. If there is divergence at upper levels there is rising air below that area of divergence. These conditions are favorable to the pyroCb developing.


250 mb Convergence(color fill), Geopotential Height (contoured every 30 m) and wind barbs every 6 hours starting on 06 January 0 UTC.

This Skew-T taken at 12 UTC on 06 January after the pyroCb located at 32.9 S 116 E. From the Skew-T it is apparent that there is a very dry air above this pyroCb.
106skewtSkew-T at 12 UTC (click to enlarge) Green line is dew point and red line is temperature.

This Skew-T taken at 12 UTC on 07 January after the pyroCb located at 32.9 S 116 E. From the Skew-T it is apparent that there is a very dry air above this pyroCb, but becomes very moist above 300 mb. This moist air could be beneficial to the develop of the pyroCbs at this time.
107skewtSkew-T at 12 UTC (click to enlarge) Green line is dew point and red line is temperature.

Interesting Possibility of PyroCu in Southern Australia

On 25 December there was a potential for some pyroCb development from fires located in southern Australia. Himawari-8 detected the smoke plume and clouds around the fires, as well as the fire hot spots. Starting at 01:30 UTC on 25 December, 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)

Himawari-8 10.4 μm IR channel imagery the minimum cloud-top IR brightness temperatures could be found. The animation below, starting at 03:00 UTC on 25 December. This fire active was not pyroconvective because the cloud top brightness temperature was not cold enough to register.

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

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

Impressive Fires in Western Australia

On 17 November there was a possibility for more pyroconvection. According to ABC News four people have died from the fire activity in region. Furthermore Rick McRae has reported that 80% of the main fire was in the wheatbelt area. This area has been known the produce pyroCbs. Furthermore, weather conditions were astounding with winds gusting at 09:46 UTC between 50 and 74 km/kr. At 06:40 UTC the temperature was 41.2°C with 2% relative humidity and a sea level pressure of 997 hPa. McRae attributes the lack of pyroCb formation to the gusting winds and not enough buoyancy to provide upward vertical motion. The following Skew-T provided by Rick McRae taken at Esperance shows the upper air conditions around these fires and the increase in dew point to 34°C.

Skew-T taken at 23 UTC on 16 November (click to enlarge)

Skew-T taken at 23 UTC on 16 November (click to enlarge)

Himawari-8 detected the smoke plume and clouds around the fires, as well as the fire hot spots. Starting at 05:00 UTC on 17 November, 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)

Himawari-8 10.4 μm IR channel imagery the minimum cloud-top IR brightness temperatures could be found. The animation below, starting at 08:00 UTC on 17 November. This fire active was not pyroconvective because the cloud top brightness temperature was not cold enough to register.

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

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

To further investigate the transport of smoke from this fire CALIPSO was used. This LIDAR shows the height of the clouds from the wildfire. The first image below is the 532nm Total Attenuated Backscatter plot on 17 November from 16:07 UTC to 16:30 UTC. The smoke from this fires can be seen ~ 35-40 S indicated faintly by a red/grey color.  The second image is 1064 nm Total Attenuated Backscatter plot, the smoke on this plot is indicated by a grey color. The third image is the Depolarization image the smoke is indicated by a light blue color. The fourth image is the Attenuated Ratio plot between 1064 nm and 532 nm. The smoke is indicated by the grey 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 the black pixels).

CALIPSO 532 nm Total Attenuated Backscatter on 17 November (click to enlarge)

CALIPSO 532 nm Total Attenuated Backscatter on 17 November (click to enlarge)

CALIPSO 1064 nm Total Attenuated Backscatter on 17  November (click to enlarge)

CALIPSO 1064 nm Total Attenuated Backscatter on 17 November (click to enlarge)

CALIPSO Depolarization Ration on 17 November (click to enlarge)

CALIPSO Depolarization Ration on 17 November (click to enlarge)

CALIPSO Attenuated Color Ratio between 1064 nm and 532 nm on 17 November (click to enlarge image)

CALIPSO Attenuated Color Ratio between 1064 nm and 532 nm on 17 November (click to enlarge image)

CALIPSO Vertical Feature Mask on 17 November (click to enlarge image)

CALIPSO Vertical Feature Mask on 17 November (click to enlarge image)

CALIPSO Aerosol Subtype plot on 17 November (click to enlarge image)

CALIPSO Aerosol Subtype plot on 17 November (click to enlarge image)

PyroCu in Western Australia

On 14 November there was a pyroCu in Western Australia at 34.6 S 116.7 E. Himawari-8 detected the smoke plume and clouds around the fires, as well as the fire hot spots. Starting at 01:00 UTC on 14 November, 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)

Himawari-8 10.4 μm IR channel imagery the minimum cloud-top IR brightness temperatures could be found. The animation below, starting at 04:30 UTC on 14 November, shows that the pyroCu reached around -35 ºC (dark blue color enhancement) around 06:00 UTC. It is hard to distinguish between the clouds from the pyroCu and clouds that are moving into the area. Since it has not reached -40 ºC it is not considered a pyroCb.

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

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

Below is an animation of the convergence at 250 mb shown by a color fill, the the 250 mb geopotential height contoured every 30 meters and the wind barbs. It has been investigated that upper level divergence is associated with the ability for pyroCu to turn into a pyroCb (Peterson et al., BAMS, Feb. 2015, 229-247). Starting at 0 UTC on 22 August the spot of the pyroCb is indicated by a white dot. This pyroCb is in an area of divergence. This is conducive to the strengthening of the pyroCb. If there is divergence at upper levels there is rising air below that area of divergence. These conditions are favorable to the pyroCb developing.


250 mb Convergence(color fill), Geopotential Height (contoured every 30 m) and wind barbs every 6 hours starting on 22 August 0 UTC.

This Skew-T taken at 06 UTC on 14 November after the pyroCu located at 34.6 S 116.7 E. From the Skew-T it is apparent that there is a good amount of CAPE which is favorable for convective development. However, there is a very moist layer that could contribute to the fact that this pyroCu never turned into a pyroCb.
skewt11.14austSkew-T at 12 UTC (click to enlarge) Green line is dew point and red line is temperature

PyroCb in California

On 10 September a pyroCb formed from the Butte fire in California (38.4 N, 120.7 W). From the CAL FIRE website, this fire started on 09 September and as of 11 September the fire has burned about 50,000 acres. GOES-15 detected the smoke plume and pyroCb cloud, as well as the fire hot spot. Starting at 21:00 UTC on 10 September, the animation below shows visible (.63 μm) on the left and shortwave IR (3.9 μm) on the right (click image to play animation). In the shortwave IR images the red pixels indicate very hot IR brightness temperatures exhibited by the fire source region.

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)

In addition, using GOES-15 10.7 μm IR channel the cloud-top IR brightness temperature could be found. The animation below, starting at 22:30 UTC on 10 September, shows the brightness temperature for the pyroCb is -46.8ºC around 01:00 UTC on 11 September (green color enhancement).

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

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

Also, HYSPLIT forward forecasting can show the estimated transport of the smoke at 8000, 9000, and 10000 m. The image starting at 00:00 UTC on 11 September shows that the smoke is expected to move eastward. Depending on how far the smoke gets in the atmosphere can determine which trajectory the smoke will follow.

HYSPLIT Forward Trajectory (click to enlarge)

HYSPLIT Forward Trajectory (click to enlarge)

OMPS AI index images (courtesy of Colin Seftor) shows the transport of smoke on 11 September and 12 September. on 11 September the max AI index of 6.9 at 36.95 N 120.09 W, which is just south of the spot of the pyroCb. From the HYSPLIT above the smoke from 11 September OMPS seems to be following the green trajectory at 10000 m.

OMPS Aerosol Index image on 11 September (click to enlarge)

OMPS Aerosol Index image on 11 September (click to enlarge)

On 12 September the max AI index of 6.5  at 40.98 N 118.31 W, which is northwest of the pyroCb. On 12 September the smoke seemed to follow the red or blue trajectory on the HYSPLIT image.

OMPS Aerosol Index image on 12 September (click to enlarge)

OMPS Aerosol Index image on 12 September (click to enlarge)

PyroCb in Montana

On 28 August there was some discussion on whether there was a pyroCb in Montana. Upon further investigation it was found that there was a pyroCb at 48.2 N 113 W. GOES-15 detected the smoke plume and pyroCb cloud, as well as the fire hot spot. Starting at 21:00 UTC on 28 August, the animation below shows visible (.63 μm) on the left and shortwave IR (3.9 μm) on the right (click image to play animation). In the shortwave IR images the red pixels indicate very hot IR brightness temperatures exhibited by the fire source region.

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)

In addition, using GOES-15 10.7 μm IR channel the cloud-top IR brightness temperature could be found. From the animation above it can be seen that there were three major convective clouds associated with this pyroCb. The animation below, starting at 21:00 UTC on 28 August, shows the brightness temperature for the pyroCbs associated with this fire. Each pyroCb has a red circle encompassing it. The first pyroCb is -67ºC around 23:00 UTC on 28 August (red color enhancement), the second pyroCb is -68ºC around 00:30 UTC on 29 August (red color enhancement), and the third pyroCb is -70ºC around 02:00 UTC on 29 August (dark red color enhancement).

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

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

The animation below is from IDEA, it shows the 48 hr forecast of the trajectory of an air parcel, along with wind models and precipitation. The animation starting on 28 August at 18 Z shows the hot spot in the southwestern part of Montana. From there the smoke from this pyroCb moves northeast towards Canada. In addition, the colors of the arrows are important. Since the arrows are a white color that is indicative of upward motion of air flow.

48-hour aerosol trajectory forecast with model winds and precipitation on 28 August

48-hour aerosol trajectory forecast with model winds and precipitation on 28 August