Blowing dust in Texas and Oklahoma

January 21st, 2018 |

GOES-16

GOES-16 “Moisture” Infrared brightness temperature difference (10.3-12.3 µm) images, with hourly surface reports plotted in cyan [click to play animation]

Strong winds in the wake of a cold frontal passage created large areas of blowing dust across the Panhandle Plains of northwestern Texas after 16 UTC on 21 January 2018. GOES-16 “Moisture” or “split-window difference” (10.3 µm12.3 µm) images (above) showed that the leading edge of this airborne dust moved over far southwestern Oklahoma after 20 UTC. (Note to AWIPS users: the default enhancement for this GOES-16 “Moisture” Channel Difference product was changed to “Grid/lowrange enhanced” to better highlight the dust with shades of yellow)

GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Cirrus” (1.37 µm) images (below) also displayed blowing dust signatures; the surface visibility was restricted to 2-3 miles at some locations, with Big Spring briefly reporting only 1/4 mile from 20-21 UTC. The dust signature was apparent on the Cirrus imagery because this spectral band can be used to detect any airborne particles that are effective scatterers of light (such as cirrus ice crystals, volcanic ash, dust/sand or haze).

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly reports of surface weather plotted in red and surface visibility (miles) plotted in red [click to play animation]

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Cirrus” (1.37 µm) images, with hourly reports of surface weather plotted in red and surface visibility (miles) plotted in red [click to play animation]

A Cirrus band is also available with the MODIS instrument on the Terra and Aqua satellites (as well as the VIIRS instrument on Suomi NPP and NOAA-20) — a comparison of Visible (0.65 µm), Cirrus (1.37 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images from Terra and Aqua (below) highlighted the differing appearance of the blowing dust features as sensed by each of those spectral bands. The airborne dust exhibited a darker signature in the Shortwave Infrared images since the small dust particles were efficient reflectors of incoming solar radiation, thus appearing warmer at 3.7 µm.

Terra MODIS Visible (0.65 µm), Cirrus (1.37 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images, with surface reports plotted in cyan [click to enlarge]

Terra MODIS Visible (0.65 µm), Cirrus (1.37 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images, with surface reports plotted in cyan [click to enlarge]

Aqua MODIS Visible (0.65 µm), Cirrus (1.37 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images, with surface reports plotted in cyan [click to enlarge]

Aqua MODIS Visible (0.65 µm), Cirrus (1.37 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images, with surface reports plotted in cyan [click to enlarge]

Pilot reports within 20-45 minutes after the Terra overpass time (below) revealed Moderate to Severe turbulence at an elevation of 8000 feet, just southeast of the most dense dust plume feature (highlighted by the cooler, lighter gray infrared brightness temperatures) — this was likely due to strong wind shear in the vicinity of the rapidly-advancing cold front. Farther to the southwest, another pilot report indicated that the top of the blowing dust was at 7000 feet, with a flight-level visibility of 3 miles at 10,000 feet.

Terra MODIS Infrared Window (11.0 µm) image, with a pilot report of turbulence highlighted in red [click to enlarge]

Terra MODIS Infrared Window (11.0 µm) image, with a pilot report of turbulence highlighted in red [click to enlarge]

Terra MODIS Infrared Window (11.0 µm) image, with a pilot report of dust layer top and flight level visibility highlighted in red [click to enlarge]

Terra MODIS Infrared Window (11.0 µm) image, with a pilot report of dust layer top and flight level visibility highlighted in red [click to enlarge]

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]

Deadly Smog in India and Pakistan

November 9th, 2017 |

Suomi NPP VIIRS Day Night Band Visible Imagery (0.70 µm) at Night, 05, 07 and 08 November 2017 (Click to enlarge).

Suomi NPP VIIRS Visible Imagery at Night (the Day Night Band Visible Image (0.7 µm) from 5 November, 7 November and 8 November), above, and Infrared Channel Brightness Temperature Difference  (11.45 µm – 3.9 µm) on 5 November, 7 November and 8 November), below, both show the presence of fog/smog over northern Pakistan and northwestern India from 05-08 November 2017 (Suomi NPP VIIRS Imagery courtesy of William Straka, CIMSS). The Smog led the Government of Punjab to ban burning of stubble; schools in Delhi were closed.  Vehicle crashes linked to reduced visibilities have killed at least 10 people (source).  Air Quality in the region is very poor as shown in this Screen Grab from this site.

Suomi NPP VIIRS Infrared channel Brightness Temperature Difference (11.45 µm – 3.9 µm) on 05, 07, and 08 November 2017 (Click to enlarge)

An animation of Meteosat-8 Visible Imagery, below, from 03-09 November, shows little improvement in conditions in the past week.

Meteosat-8 Visible Imagery (0.6 µm) at 0300 UTC from 03 to 09 November 2017 (Click to enlarge)

Daily composites of Suomi NPP VIIRS true-color Red-Green-Blue (RGB) images from RealEarth, below, showed the areal coverage of the smog during the 03-09 November period. Surface observations at New Delhi’s Indira Gandhi International Airport indicated that the visibility remained below one statute mile — with zero visibility at times — during the 72-hour period spanning 07 November, 08 November and 09 November (animation).

Daily composites of Suomi NPP VIIRS true-color RGB images (click to enlarge)

Daily composites of Suomi NPP VIIRS true-color RGB images (click to enlarge)

Worth noting on a nighttime comparison of Suomi NPP VIIRS Infrared Brightness Difference (11.45-3.74 µm) and Day/Night Band (0.7 µm) images, below, was the appearance of a cloud shadow being cast by moonlight onto the top of the boundary layer smog/fog.

Suomi NPP VIIRS Infrared Brightness Difference (11.45-3.74 µm) and Dat/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Infrared Brightness Difference (11.45-3.74 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Wildfires in Northern California

October 9th, 2017 |

GOES-16 Shortwave Infrared (3.9 µm) images, with county outlines plotted in gray (dashed) and surface station identifiers plotted in white [click to play MP4 animation]

GOES-16 Shortwave Infrared (3.9 µm) images, with county outlines plotted in gray (dashed) and surface station identifiers plotted in white [click to play MP4 animation]

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

GOES-16 Shortwave Infrared (3.9 µm) images (above) showed the “hot spot” signatures (black to yellow to red pixels) associated with numerous wildfires that began to burn in Northern California’s Napa County around 0442 UTC on 09 October 2017 (9:42 PM local time on 08 October). A strong easterly to northeasterly Diablo wind (gusts) along with dry fuels led to extreme fire behavior, with many of the fires quickly exhibiting very hot infrared brightness temperature values and growing in size at an explosive rate (reportedly burning 80,000 acres in 18 hours).

A comparison of nighttime GOES-16 Shortwave Infrared (3.9 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (below) offered another example of nocturnal fire signature identification — the bright glow of the fires showed up well on the 1-km resolution 1.61 µm imagery. Especially noteworthy was the very rapid southwestward run of the Tubbs Fire, which eventually moved just south of station identifier KSTS (Santa Rosa Sonoma County Airport; the city of Santa Rosa is located about 5 miles southeast of the airport. These Northern California fires have resulted in numerous fatalities, destroyed at least 3500 homes and businesses, and forced large-scale evacuations (media story).

GOES-16 Shortwave Infrared (3.9 µm, left) and Near-Infrared

GOES-16 Shortwave Infrared (3.9 µm, left) and Near-Infrared “Snow/Ice” (1.61 µm, right) images [click to play MP4 animation]

A toggle between 1007 UTC (3:07 AM local time) Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) images (below) provided a view of the fires at an even higher spatial resolution. Since the Moon was in the Waning Gibbous phase (at 82% of Full), it provided ample illumination to highlight the dense smoke plumes drifting west-southwestward over the adjacent offshore waters of the Pacific Ocean.

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

A closer VIIRS image comparison (with county outlines) is shown below.

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

A comparison of Suomi NPP VIIRS true-color and false-color Red-Green-Blue (RGB) images from RealEarth (below) helped to discriminate between smoke and cloud features offshore over the Pacific Ocean.

Suomi NPP VIIRS True-color and False-color RGB images [click to enlarge]

Suomi NPP VIIRS True-color and False-color RGB images [click to enlarge]

===== 10 October Update =====
Suomi NPP VIIRS true-color and false-color images [click to enlarge]

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

With the switch to southwesterly surface winds on 10 October, smoke plumes could be seen moving northeastward on RealEarth VIIRS true-color imagery, while the burn scars of a number of the larger fires became apparent on VIIRS false-color RGB imagery (above).

===== 11 October Update =====

Landsat-8 false-color RGB images, from 04 October (before the Tubbs Fire) and 11 October (after the Tubbs Fire) [click to enlarge]

Landsat-8 false-color RGB images, from 04 October (before the Tubbs Fire) and 11 October (after the Tubbs Fire) [click to enlarge]

A toggle (above)  between 30-meter resolution Landsat-8 false-color RGB images from 04 October (before the Tubbs Fire) and 11 October (after the Tubbs Fire) showed the size of the fire burn scar (shades of brown) which extended southwestward from the fire source region into Santa Rosa.

===== 12 October Update =====
Suomi NPP VIIRS true-color RGB images, with VIIRS-detected fire locations [click to enlarge]

Suomi NPP VIIRS true-color RGB images, with VIIRS-detected fire locations [click to enlarge]

A transition back to northerly winds on 12 October helped to transport the wildfire smoke far southward over the Pacific Ocean (above). Smoke was reducing surface visibility and adversely affecting air quality at locations such as San Francisco (below).

Time series plot of surface observations at San Francisco International Airport [click to enlarge]

Time series plot of surface observations at San Francisco International Airport [click to enlarge]

Suomi NPP VIIRS Aerosol Optical Depth values were very high — at or near 1.0 — within portions of the dense smoke plume (below).

Suomi NPP VIIRS true-color RGB image and Aerosol Optical Depth product [click to enlarge]

Suomi NPP VIIRS true-color RGB image and Aerosol Optical Depth product [click to enlarge]