Day 7 of the Thomas Fire in Southern California

December 10th, 2017 |

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

The Thomas fire began burning in Southern California around 6:30 PM local time on 04 December (blog post) — and on 10 December 2017, GOES-15 (GOES-West) Shortwave Infrared (3.9 µm) images (above) revealed that the fire showed little signs of diminishing during the nighttime hours, and in fact began to exhibit a trend of intensification around 05 UTC or 9 PM local time. However, toward the end of the day on 10 December, bands of  thick cirrus clouds moving over the fire region acted to dramatically attenuate the satellite-detected thermal signature of the fire complex. Although the Santa Ana winds were not as intense as they had been during the previous week, some strong wind gusts were still observed.

A sequence of 4 Shortwave Infrared images from Terra MODIS and Suomi NPP VIIRS (below) showed the westward and northwestward expansion of the fire during the 0637 to 2032 UTC period. The Thomas fire has now burned 230,000 acres, making it the fifth largest wildfire on record in California.

Terra MODIS and Suomi NPP VIIRS Shortwave Infrared images, with corresponding surface reports plotted in cyan [click to enlarge]

Terra MODIS and Suomi NPP VIIRS Shortwave Infrared images, with corresponding surface reports plotted in cyan [click to enlarge]

In a toggle between Terra MODIS true-color and false-color Red-Green-Blue (RGB) images at 1846 UTC (below; source) the true-color image revealed a broad plume of thick smoke being transported westward and northwestward from the fire source region, while the false-color image showed the areal coverage of the burn scar (which appeared as reddish-brown hues beneath the clouds) as well as locations of the larger and more intense active fires (brighter pink to white) that were burning along the northern to western perimeter of the burn scar.

Terra MODIS true-color and false-color images [click to enlarge]

Terra MODIS true-color and false-color images [click to enlarge]

A comparison of Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images at 2032 UTC or 12:32 PM  local time (below) showed a well-defined thermal signature before the thicker cirrus clouds moved overhead from the south. A small cloud cluster (located just northwest of the fire thermal signature) exhibited a minimum infrared brightness temperature of -43ºC — if this cloud feature was indeed generated by the fire complex, it meets the -40ºC criteria of a pyrocumulonimbus cloud.

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images, with surface reports plotted in cyan [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images, with surface reports plotted in cyan [click to enlarge]

The fire was producing very thick smoke, in addition to deep pyrocumulus clouds (top photo taken around 1945 UTC or 11:45 AM local time):

Shown below is a photo taken at 2045 UTC or 12:45 PM local time, from a commercial jet flying into Santa Barbara (courtesy of Henry Dubroff/www.pacbiztimes.com).

Photo of Thomas Fire pyrocumulus [click to enlarge]

Photo of Thomas Fire pyrocumulus [click to enlarge]

===== 11 December Update =====
 

Suomi NPP VIIRS Day/Night Band (0.7 µm), Near-Infrared (1.61 and 2.25 µm), Shortwave Infrared (3.75 and 4.05 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm), Near-Infrared (1.61 and 2.25 µm), Shortwave Infrared (3.75 and 4.05 µm) and Infrared Window (11.45 µm) images [click to enlarge]

A toggle between Suomi NPP VIIRS Day/Night Band (0.7 µm), Near-Infrared (1.61 and 2.25 µm), Shortwave Infrared (3.75 and 4.05 µm) and Infrared Window (11.45 µm) images at 1035 UTC or 2:35 AM local time (above; courtesy of William Straka, CIMSS) demonstrated how different spectral bands can be used to detect nighttime fire signatures. The maximum infrared brightness temperature on the 4.05 µm image was 389 K (115.9ºC or 240.5ºF). Note that the recently-launched JPSS-1/NOAA-20 satellite also carries a VIIRS instrument.

GOES-15 Shortwave Infrared (3.9 µm) images (below) showed that once the thicker bands of cirrus clouds moved northwestward away from the region, a more well-defined thermal signature became apparent.

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly surface reports plotted in yellow [click to play animation]

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly surface reports plotted in yellow [click to play animation]

A 7-day sequence Nighttime and Daytime composites of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images (source: RealEarth) is shown below — it illustrates the spread of the Thomas Fire from 05 December to 11 December. Hot infrared pixels are black, with saturated pixels appearing bright white.

7-day sequence Nighttime and Daytime composites of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images [click to play animation]

7-day sequence Nighttime and Daytime composites of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images [click to play animation]

Wildfires in southern California

December 5th, 2017 |

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly surface plots [click to play MP4 animation]

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly surface plots [click to play MP4 animation]

GOES-15 (GOES-West) Shortwave Infrared (3.9 µm) images (above; also available as an animated GIF) showed the rapid development of wildfires driven by strong Santa Ana winds in Southern California on 05 December 2017. The fire thermal anomalies or “hot spots” are highlighted by the dark black to yellow to red pixels — the initial signature was evident on the 0230 UTC image (6:30 PM local time on 04 December), however the GOES-15 satellite was actually scanning that particular area at 0234 UTC or 6:34 PM local time. The Thomas Fire (the largest of the fires) advanced very quickly toward the southwest, nearly reaching the coast.

Nighttime image toggles between Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) data at 0904 UTC and 1044 UTC (below) revealed the large fire hot spots, along with the extensive smoke plume that was drifting over the adjacent nearshore waters of the Pacific Ocean. With ample illumination from the Moon (which was in the Waning Gibbous phase, at 95% of Full), the “visible image at night” capability of the VIIRS Day/Night Band — which will also be available from the recently-launched JPSS-1/NOAA-20 satellite — was clearly demonstrated.

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) images, with plots of surface reports [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) images, with plots of surface reports [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) images, with plots of surface reports [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) images, with plots of surface reports [click to enlarge]

A toggle between the two VIIRS Day/Night Band images (below; courtesy of William Straka, CIMSS) showed initial darkness resulting from fire-related power outages in Santa Barbara County to the north, and Ventura County to the south (in the Oxnard/Camarillo area).

Suomi NPP VIIRS Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) images [click to enlarge]

This large wind-driven fire was also very hot — the maximum brightness temperature on the VIIRS 4.05 µm Shortwave Infrared image was 434.6 K or 322.6º F, which was above the saturation threshold of the VIIRS 3.75 µm Shortwave Infrared detectors (below).

Suomi NPP VIIRS 4.05 µm and 3.75 µm Shortwave Infrared images [click to enlarge]

Suomi NPP VIIRS 4.05 µm and 3.75 µm Shortwave Infrared images [click to enlarge]

In a comparison of daytime GOES-15 Visible (0.63 µm) and Shortwave Infrared (3.9 µm) images (below), the west-southwestward transport of smoke over the Pacific Ocean was clearly seen.

GOES-15 Visible (0.63 µm, top) and Shortwave Infrared (3.9 µm, bottom) images [click to play MP4 animation]

GOES-15 Visible (0.63 µm, top) and Shortwave Infrared (3.9 µm, bottom) images [click to play MP4 animation]

A more detailed view of the thick smoke originating from the 3 fires (from north to south: the Thomas, Rye and Creek fires) was provided by a 250-meter resolution Aqua MODIS true-color Red-Green-Blue (RGB) image from the MODIS Today site (below).

Aqua MODIS true-color RGB image [click to enlarge]

Aqua MODIS true-color RGB image [click to enlarge]

Immediately downwind of the Creek Fire, smoke was reducing the surface visibility to 1 mile at Van Nuys and adversely affecting air quality (below).

Time series plot of surface reports at Van Nuys, California [click to enlarge]

Time series plot of surface reports at Van Nuys, California [click to enlarge]

===== 06 December Update =====

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.75 µm and 4.05 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.75 µm and 4.05 µm) images [click to enlarge]

The fires in Southern California continued to burn into the following night, as shown by Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.75 µm and 4.05 µm) images (above; courtesy of William Straka, CIMSS). A large-scale view with Day/Night Band imagery revealed the extent of smoke transport westward over the Pacific Ocean.

GOES-15 Shortwave Infrared (3.9 µm) images (below) displayed the thermal signatures exhibited by the fires. Note the appearance of a new fire — the Skirball Fire — first appearing on the 1300 UTC (5:00 AM local time) image, just north of Santa Monica (KSMO). Although the Santa Ana winds were not quite as strong as the previous day, some impressive wind gusts were still reported.

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly surface plots [click to play MP4 animation]

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly surface plots [click to play MP4 animation]

A toggle between 250-meter resolution Terra (1911 UTC) & Aqua (2047 UTC) MODIS true-color images from MODIS Today (below) showed significant pyrocumulus development from a flare-up along the northeast perimeter of the Thomas Fire. The cloud plume only exhibited a minimum infrared brightness temperature of +5.5º C on the corresponding Aqua MODIS Infrared Window image, far above the -40ºC threshold assigned to pyroCumulonimbus clouds.

Comparison of Terra (1911 UTC) & Aqua (2047 UTC) MODIS true-color RGB images [click to enlarge]

Comparison of Terra (1911 UTC) & Aqua (2047 UTC) MODIS true-color RGB images [click to enlarge]

===== 07 December Update =====

Suomi NPP Day Night Band Imagery, 3-7 December 2017, over southern California

RealEarth imagery of the Day Night Band over 5 days (one image each night from 3 through 7 December), above, shows the evolution of the fire complex (Imagery courtesy Russ Dengel, SSEC). Similarly, a closer view of daily composites of VIIRS Shortwave Infrared (3.74 µm) imagery (below) revealed the growth and spread of the Thomas Fire from 04-07 December.

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) image composites [click to enlarge\

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) image composites [click to enlarge]

In a toggle between Terra MODIS true-color and false-color RGB images (below), the large burn scar of the Thomas Fire (shades of red to brown) was very apparent on the false-color image.

Terra MODIS true-color and false-color images [click to enlarge]

Terra MODIS true-color and false-color images [click to enlarge]

Prescribed burn in Wisconsin

November 28th, 2017 |

GOES-16 Visible (0.64 µm, left) and Shortwave Infrared (3.9 µm, right) images, with plots of hourly surface reports [click to play MP4 animation]

GOES-16 Visible (0.64 µm, left) and Shortwave Infrared (3.9 µm, right) images, with plots of hourly surface reports [click to play MP4 animation]

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

GOES-16 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above; also available as an animated GIF) showed signatures associated with a prescribed burn in western Wisconsin on 28 November 2017. The Shortwave Infrared images revealed a warm thermal anomaly or “hot spot” (dark black to yellow to red pixels) — and on the visible images, a thin smoke plume could be seen drifting southeastward from the fire source.

Early in the animation sequence, however, a band of cirrus cloud was moving over the fire — yet a faint thermal signature (darker gray to black pixels) could occasionally be seen on the Shortwave Infrared imagery. The cirrus cloud layer was thin enough to allow some of the heat energy emitted by the fire to pass through and reach the satellite detectors. Once the cirrus moved to the south, the fire’s hot spot became much more apparent.

A toggle between Terra MODIS Shortwave Infrared (3.7µm) and Infrared Window (11.0 µm) images at 1812 UTC (below) also showed a faint warm fire signature through the cirrus clouds — the cloud-top Infrared Window brightness temperature directly over the fire in northern Monroe County was -33ºC, while the warmest Shortwave Infrared brightness temperature of the subtle fire signature was +1ºC.

Terra MODIS Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images [click to enlarge]

Terra MODIS Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images [click to enlarge]

As was seen on the GOES-16 imagery, after the band of cirrus moved south of the fire an Aqua MODIS Shortwave Infrared (3.7 µm) image at 1912 UTC (below) displayed a pronounced fire hot spot signature.

Aqua MODIS Shortwave Infrared (3.7 µm) image [click to enlarge]

Aqua MODIS Shortwave Infrared (3.7 µm) image [click to enlarge]

(Thanks to Dave Schmidt, NWS La Crosse, for bringing this case to our attention!)

GOES-16 Tools to Observe and Monitor Fires

October 9th, 2017 |

GOES-16 Visible (0.64 µm) Imagery, 1522-2017 UTC on 9 October 2017 (Click to animate)

GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing.

GOES-16 provides many tools to the Operational Meteorologist, and to National Weather Service Incident Meteorologists (IMETs), to monitor fires when they occur, such as those over Napa and Sonoma Counties in California (Blog Post). Visible (0.64 µm) and Shortwave Infrared (3.9 µm) channels, above and below, respectively, are available routinely at 5-minute intervals over the Continental United States. During daytime, the Visible Imagery is useful for highlighting smoke palls and for alerting meteorologists to any wind changes. The Shortwave Infrared has long been used to detect fires; the shortwave infrared channel on GOES-16 can detect hotter and smaller fires than previous GOES Satellites because of improved spatial resolution and improved bit depth in the imagery.

GOES-16 Shortwave Infrared (3.9 µm) Imagery, 1522-2017 UTC on 9 October 2017 (Click to animate)

GOES-16 Channels can be combined to create Red Green Blue (RGB) Composites that also help identify fires qualitatively. The Fire RGB, below, combines the shortwave IR (3.9 µm) with the 2.2 µm and 1.6 µm channels; as fires get warmer, radiation is emitted at shorter and shorter wavelengths. When this RGB shows white values, you can be certain that the fire is very hot. At some times in the RGB animation, the 3.9 µm imagery is missing where the fire is exceptionally hot, meaning the ‘red’ component of the RGB has no value, and the RGB acquires a blue and green hue.

GOES-16 Fire Temperature RGB, 1522 – 2017 UTC on 9 October 2017 (Click to animate)

The Fire Temperature RGB like the visible imagery shown above offer qualitative information about fire. More quantitative information is available in GOES-16 Baseline Products that are an extension and refinement of the WF-ABBA products available for GOES-13 and GOES-15 (and other satellites). Fire-related products for GOES-16 include Fire Area and Fire Temperature, shown below. The products give the size of the fire within the pixel, and its temperature. These products are valuable in quickly evolving fires to monitor how things change, and the products are available every 5 minutes.

GOES-16 Fire Area Derived Product, 1522-2017 UTC on 9 October 2017 (Click to animate)

GOES-16 Fire Temperature, 1522-2017 UTC on 9 October 2017 (Click to animate)

Finally, GOES-16 has 1-minute Mesoscale Sectors that can be used to closely monitor quickly-evolving fire situations. The 3.9 µm shortwave infrared and Fire RGB images are shown below for a two-hour period. There can be significant changes to a fire in 1 minute, as was seen in this Blog Post! Note again that missing points in the 3.9 µm imagery will show up as green or blue regions in the RGB.

Fire RGB Product, 1931-2130 UTC on 9 October 2017 (Click to animate)

GOES-16 Shortwave Infrared (3.9 µm), 1933 – 2132 UTC on 9 October 2017 (Click to animate)