Slide Fire in Arizona

May 22nd, 2014
GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

McIDAS images of GOES-13 (GOES-East) 0.63 µm visible channel data (above; click image to play animation) showed the rapid growth of the smoke plume from the Slide Fire which was burning in Arizona on 21 May 2014.

As the fire continued to burn into the night, a comparison of AWIPS images of 375-meter resolution Suomi NPP VIIRS 3.74 µm and 4-km resolution GOES-13 3.9 µm shortwave IR images (below) demonstrated the advantage of improved spatial resolution (and a more direct viewing angle) of the VIIRS data for determining both the intensity and the true location of the fire hot spots around 10 UTC or 4 am local time.

Suomi NPP VIIRS 3.74 µm and GOES-13 3.9 µm shortwave IR image comparison

Suomi NPP VIIRS 3.74 µm and GOES-13 3.9 µm shortwave IR image comparison

On the following morning, GOES-15 (GOES-West) 0.63 µm visible channel images (below; click to play animation) the smoke plume aloft and smoke which had settled into valleys could be seen during the early morning hours.

GOES-15 0.63 µm visible channel images (click to play animation)

GOES-15 0.63 µm visible channel images (click to play animation)

Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images from 21 May and 22 May are visualized using the SSEC RealEarth web map server (below). On 22 May, bands of high-altitude cirrus clouds were moving over the region, making the identification of the north/northwestward-moving smoke plume a bit more difficult.

Suomi NPP VIIRS true-color RGB images (21 and 22 May)

Suomi NPP VIIRS true-color RGB images (21 and 22 May)

Cyclonic transport of fire smoke over the Gulf of Alaska

May 21st, 2014
GOES-15 0.63 µm visible channel images (click to play animation)

GOES-15 0.63 µm visible channel images (click to play animation)

McIDAS images of GOES-15 0.63 µm visible channel data (above; click image to play animation) showed the cyclonic transport of smoke across the Gulf of Alaska on 20 May 2014. The source of the smoke was the Funny River Fire that was burning on the Kenai Peninsula of south-central Alaska, near Soldotna. The fire quickly grew to 20,000 acres in about 24 hours.

The curved smoke plume was also quite evident on 3 separate Suomi NPP VIIRS 0.7 µm Day/Night Band images (below). Smoke was reducing the surface visibility as low as 3 miles at Homer (station identifier PAHO).

Suomi NPP VIIRS 0.7 µm Day/Night Band images

Suomi NPP VIIRS 0.7 µm Day/Night Band images

Even though patchy clouds covered the Kenai Peninsula region around 13 UTC, the fire “hot spots” (black to yellow to red color enhancement) were still detectable on the VIIRS 3.74 µm shortwave IR image (below).

Suomi NPP VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR channel images

Suomi NPP VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR channel images

Southern California wildfires

May 15th, 2014
GOES-15 0.63 µm visible channel images (click to play animation)

GOES-15 0.63 µm visible channel images (click to play animation)

With an ongoing extreme to exceptional drought, hot temperatures (daily high temperatures along the coastal areas as high as 106º F at John Wayne Airport) combined with strong offshore Santa Ana winds (gusting as high as 87 mph at Big Black Mountain) conspired to create an environment favorable for wildfires across southern California and northern Baja California on 14 May 2014. McIDAS images of GOES-15 0.63 µm visible channel data (above; click image to play animation) showed a number of smoke plumes streaming off the coast during the day. Note the brief appearance of a cluster of bright white pixels on the 18:00 UTC image, just north of the California/Baja California border — this a signal of sunlight being reflected off of large solar panel arrays in that area.

The side-by-side comparison of GOES-15 (GOES-West) and GOES-13 (GOES-East) 0.63 µm visible channel images (below) showed that with a lowering sun angle at the end of the day, the smoke plumes began to become more difficult to identify on GOES-15 images (left); on the other hand, thanks to the benefit of a favorable forward scattering angle, the areal coverage of the smoke plumes stood out very well on GOES-13 images (right). The enhancements are the same on both sets of images.

GOES-15 (left) and GOES-13 (right) 0.63 µm visible channel images

GOES-15 (left) and GOES-13 (right) 0.63 µm visible channel images

A 375-meter resolution Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image visualized using the SSEC RealEarth web map server (below) showed these smoke plumes with great clarity at 20:25 UTC or 1:25 PM local time.

Suomi NPP VIIRS true-color RGB image

Suomi NPP VIIRS true-color RGB image

As the larger fires continued to burn into the subsequent overnight hours, their hot thermal signature could be detected on AWIPS images of 4-km resolution GOES-15 3.9 µm shortwave IR channel data (below; click image to play animation).

GOES-15 3.9 µm shortwave IR images (click to play animation)

GOES-15 3.9 µm shortwave IR images (click to play animation)

A nighttime comparison of a 375-meter resolution Suomi NPP VIIRS 3.74 µm shortwave IR image with the corresponding 750-meter resolution VIIRS Day/Night Band image (below) showed a prominent fire hot spot (yellow to red pixels) on the shortwave IR image between San Diego (KSAN) and Camp Pendleton (KNFG), along with light gray signature of the narrow, fresh smoke plume that was being blown off the coast from that fire on the Day/Night Band image. At the time of the image, smoke was restricting the surface visibility to 5 miles at Camp Pendleton. Farther offshore, reflected moonlight was helping to show the location of smoke that had spread out over the adjacent waters of the Pacific Ocean from the previous day of burning.

Suomi NPP VIIRS 3.74 µm shortwave IR and 0.7 µm Day/Night Band images

Suomi NPP VIIRS 3.74 µm shortwave IR and 0.7 µm Day/Night Band images

Finally, a demonstration of the importance of higher spatial resolution for accurate fire hot spot detection: on the comparison of 375-meter resolution Suomi NPP VIIRS 3.74 µm and 4-km resolution GOES-15 3.9 µm shortwave IR images (below), note that although the size of the fire “hot spot” was smaller on the VIIRS image, the highest IR brightness temperature was 54.5º C (compared to 48.0º C on the GOES-15 image). In addition, the two smaller fires burning in northern Baja California were not detected on the GOES-15 image.

Suomi NPP VIIRS 3.74 µm and GOES-15 3.9 µm shortwave IR images

Suomi NPP VIIRS 3.74 µm and GOES-15 3.9 µm shortwave IR images

Fatal wildfire in Valparaíso, Chile

April 13th, 2014
GOES-13 3.9 µm shortwave IR channel images

GOES-13 3.9 µm shortwave IR channel images

Strong winds helped a wildfire to spread very quickly through a portion of the city of Valparaíso, Chile — this fire forced large-scale evacuations, destroyed around 2000 homes, and was responsible for 12 fatalities. McIDAS images of 4-km resolution GOES-13 3.9 µm shortwave IR channel data (above) showed the fire “hot spot” (black to red color enhancement), which began late in the day on 12 April 2014, and burned through the night and into the day on 13 April. The hottest 3.9 µm IR brightness temperatures were 339.6 K (66.45º C) at 20:45 UTC and 340.8 K (67.65º C) at 23:45 UTC on 12 April.

Since the GOES-13 satellite only performs one full-disk scan (hence imaging the Southern Hemisphere) every 3 hours, the temporal behavior of this fire cannot be well ascertained. The ABI instrument on the future GOES-R satellite will perform a full-disk scan every 5 minutes.

Comparisons of 1-km resolution GOES-13 visible channel images and 4-km resolution GOES-13 3.9 µm shortwave IR images (below) showed that the narrow fire smoke plume spread rapidly to the northwest.

GOES-13 0.63 µm visible channel (left) and 3.9 µm shortwave channel images (right)

GOES-13 0.63 µm visible channel (left) and 3.9 µm shortwave channel images (right)

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Suomi NPP VIIRS 3.74 µm shortwave IR image

Suomi NPP VIIRS 3.74 µm shortwave IR image

A 375-meter resolution Suomi NPP VIIRS 3.74 µm (Band I4) shortwave IR image at 05:41 UTC (above) showed greater detail of the wildfire hot spot, which exhibited a maximum IR brightness temperature of 367.0 K (93.85º C). 367 K is actually the saturation temperature for the VIIRS Band I4 detectors, indicating that this was a very hot fire. Valparaiso is located about 112 km or 70 miles west-northwest of Santiago, Chile (station identifier SCEL).

By comparison, the 4-km resolution GOES-13 3.9 µm shortwave IR image close to that time (below) indicated that the maximum IR brightness temperature of the wildfire hot spot was only 316.5 K (43.35º C).

Suomi NPP VIIRS 3.74 µm shortwave IR channel image (left) and GOES-13 3.9 µm shortwave IR channel image (right)

Suomi NPP VIIRS 3.74 µm shortwave IR channel image (left) and GOES-13 3.9 µm shortwave IR channel image (right)

McIDAS-V images of VIIRS 3.9 µm (Band M15) shortwave IR and 0.7 µm Day/Night Band (DNB) data (below; courtesy of William Straka, CIMSS/SSEC) revealed that the large fire hot spot (yellow to red color enhancement on the shortwave IR image) was adjacent to and encroaching upon the bright night-time city lights of the Valparaiso area (as seen on the Day/Night Band image). In addition, ample illumination from a nearly-full Moon allowed the smoke plume to be seen on the DNB image, as it drifted northwestward over the adjacent waters of the Pacific Ocean.

Suomi NPP VIIRS 3.9 µm shortwave IR and 0.7 µm Day/Night Band images

Suomi NPP VIIRS 3.9 µm shortwave IR and 0.7 µm Day/Night Band images

Fires had been burning in parts of Chile since January 2014. Additional information on this Valparaíso fire can be found on the Wildfire Today site.