Smoke in the Gulf of Mexico

April 18th, 2019 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with surface fronts plotted in cyan [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed some clearing of the dense pall of smoke across the far western Gulf of Mexico in the wake of a cold front that was moving southward/southeastward off the Texas coast on 18 April 2019. The parallel wave clouds of an undular bore were also evident ahead of the cold front from 13-16 UTC — the bore was also causing horizontal convective roll perturbations in the smoke about 20-40 miles ahead of the wave clouds (1506 UTC image).

The hazy signature of smoke was better defined in GOES-16 True Color Red-Green-Blue (RGB) images from the AOS site (below). This smoke was the result of widespread annual Springtime agricultural burning across southern Mexico, Guatemala, Belize and Honduras. Toward the end of the day, additional small plumes of smoke and blowing dust could  be seen moving back across the Gulf of Mexico into the “cleaner” air behind the cold front.

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images [click to play animation | MP4]

Thermal anomalies or “hot spots” (yellow to red pixels) associated with the larger fires in Mexico, Guatemala, Belize and Honduras could be seen in GOES-16 Shortwave Infrared (3.9 µm) images (below).

GOES-16 Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

GOES-16 Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

A map of fires detected by Suomi NPP VIIRS on the previous day is shown below, as viewed using RealEarth.

Fires detected by Suomi NPP VIIRS on 17 April [click to enlarge]

Fires detected by Suomi NPP VIIRS on 17 April [click to enlarge]

Large-scale blowing dust event

April 10th, 2019 |

GOES-16 Split Window (10.3-12.3 µm) images [click to play animation | MP4]

GOES-16 Split Window (10.3-12.3 µm) images [click to play animation | MP4]

Strong winds — gusting as high as 77 mph in New Mexico and 88 mph in Texas — associated with a rapidly-intensifying midlatitude cyclone generated large plumes of blowing dust (originating from southeastern Arizona,southern New Mexico, northern Mexico and western Texas) on 10 April 2019. GOES-16 (GOES-East) Split Window (10.3-12.3 µm) images (above) helped to highlight the areas of blowing dust, which initially developed along and behind a cold front after 15 UTC.

GOES-16 Split Window (10.3-12.3 µm) images, with hourly plots of surface winds and gusts [click to play animation | MP4]

GOES-16 Split Window (10.3-12.3 µm) images, with hourly plots of surface wind barbs and gusts [click to play animation | MP4]

GOES-16 Split Window images with hourly plots of surface wind barbs and gusts (above) showed the distribution of strong winds across the region, while plots of the surface visibility (below) showed decreases to 1/4 mile at Deming, New Mexico, 1/2 mile at Lubbock, Texas and 4 miles at Altus, Oklahoma.

GOES-16 Split Window (10.3-12.3 µm) images, with hourly plots of surface visibility [click to play animation | MP4]

GOES-16 Split Window (10.3-12.3 µm) images, with hourly plots of surface visibility [click to play animation | MP4]

GOES-16 True Color Red-Green-Blue (RGB) images (below; courtesy of Rick Kohrs, SSEC) depicted the blowing dust as shades of tan to light brown. Willcox Playa was the source of the dust plume coming from southeastern Arizona. Note that the dust plume emanating from White Sands, New Mexico was lighter in appearance compared to the other tan/brown-colored areas of blowing dust — this is due to the white gypsum sand that comprises the surface of White Sands National Monument.

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images [click to play animation | MP4]

250-meter resolution MODIS True Color RGB images from the MODIS Today site (below) provided a more detailed view of the plume streaming northeastward from its White Sands source. On the later Aqua image, dense tan-colored areas of blowing dust had developed below the thin higher-altitude veil of brighter gypsum aerosols that had earlier been lofted from White Sands.

MODIS True Color RGB images from Terra and Aqua [click to enlarge]

MODIS True Color RGB images from Terra and Aqua [click to enlarge]

A NOAA-20 True Color RGB image viewed using RealEarth is shown below. 19 UTC surface observations at 3 sites near White Sands included Las Cruces KLRU (visibility 3 miles, wind gusting to 46 knots), Alamogordo KALM (visibility 3 miles, wind gusting to 43 knots) and Ruidoso KSRR (visibility 5 miles, wind gusting to 55 knots). The strong winds and dense areas of blowing dust reducing surface visibility not only impacted ground transportation but also posed a hazard to aviation.

NOAA-20 True Color RGB image at 1928 UTC [click to enlarge]

NOAA-20 True Color RGB image at 1928 UTC [click to enlarge]

===== 11 April Update =====

In a larger-scale view of GOES-16 Split Window images (below), the yellow dust signature could be followed during the subsequent overnight hours and into the following day on 11 April, as the aerosols were being transported northeastward across the Upper Midwest. There were widespread reports and photos of dust residue on vehicles and tan/brown-colored snow in parts of Nebraska, Iowa, Minnesota and Wisconsin.

GOES-16 Split Window (10.3-12.3 µm) images [click to play animation | MP4]

GOES-16 Split Window (10.3-12.3 µm) images [click to play animation | MP4]

IDEA forward trajectories (below) — initialized from a cluster of elevated Aura OMI Aerosol Index points over Mexico, New Mexico and Texas — passed directly over areas of model-derived precipitation across the Upper Midwest, providing further support of precipitation scavenging of dust aerosols. Interestingly, a similar event of long range dust transport occurred on 10-11 April 2008.

IDEA forward trajectories initialized from a cluster of elevated Aqua MODIS Aerosol Optical Depth points over NM/TX [click to play animation]

IDEA forward trajectories initialized from a cluster of elevated Aqua MODIS Aerosol Optical Depth points over NM/TX [click to play animation]

HYSPLIT model 24-hour forward trajectories initialized at 3 locations — El Paso, Lubbock and Amarillo in Texas — showed a few of the likely dust transport pathways toward the Upper Midwest at 3 different levels (below).

HYSPLIT model forward trajectories initialized at El Paso, Lubbock and Amarillo, Texas [click to enlarge]

HYSPLIT model 24-hour forward trajectories initialized at El Paso, Lubbock and Amarillo, Texas [click to enlarge]

GOES-16 True Color RGB images from the AOS site (below) showed that some clouds across the Upper Midwest exhibited a subtle light brown hue at times.

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images [click to play animation | MP4]

===== 12 April Update =====

GOES-16 Split Window (10.3-12.3 µm) images [click to play animation | MP4]

GOES-16 Split Window (10.3-12.3 µm) images [click to play animation | MP4]

GOES-16 Split Window (10.3-12.3 µm) images (above) showed that the yellow signature of dust aerosols aloft had wrapped all the way around the southern and eastern sectors of the occluded low on 12 April.

Ground-based lidar at the University of Wisconsin – Madison confirmed the presence of elevated levels of aerosol loading between the surface and 6 km.

Lidar aerosol class [click to enlarge]

Lidar aerosol class [click to enlarge]

Blowing dust in southern Nevada

April 9th, 2019 |

GOES-17 Split Window (10.3-12.3 µm), Split Cloud Top Phase (11.2-8.4 µm) and

GOES-17 Split Window (10.3-12.3 µm), Split Cloud Top Phase (11.2-8.4 µm) and “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-17 (GOES-West) Split Window (10.3-12.3 µm), Split Cloud Top Phase (11.2-8.4 µm) and “Red” Visible (0.64 µm) images (above) displayed a plume of blowing dust — whose source region was a dry lake bed along the California-Nevada border — which developed in advance of an approaching cold front (surface analyses) and moved northeastward across far southern Nevada on 09 April 2019. Wind gusts of 50-65 mph were reported across the region.

This dust plume was also apparent over far southern Nevada in GOES-17 True Color Red-Green-Blue (RGB) images from the AOS site (below).

GOES-17 True Color RGB images [click to play animation | MP4]

GOES-17 True Color RGB images [click to play animation | MP4]

There are 5 airports located in the Las Vegas Valley, and GOES-17 images showed that the dust plume passed directly over Henderson (KHND) — time series plots of surface data from these sites (below) indicated that visibility was reduced to 3 miles at Henderson, with visibilities dropping to 8-9 miles at McCarran International Airport (KLAS) and Nellis Air Force Base (KLSV). The visibility was not impacted at the North Las Vegas Airport (KVGT), with its more northwest location being farther from the dust plume.

Time series plot of surface data at Henderson [click to enlarge]

Time series plot of surface data at Henderson [click to enlarge]

Time series plot of surface data at McCarran International Airport [click to enlarge]

Time series plot of surface data at McCarran International Airport [click to enlarge]

Time series plot of surface data at Nellis Air Force Base [click to enlarge]

Time series plot of surface data at Nellis Air Force Base [click to enlarge]

A notable exception was the Boulder City Municipal Airport (KBVU), which was downwind of a smaller local point source of blowing dust (Mursha Reservoir, another dry lake bed to the southwest) — the visibility at KBVU was restricted to 2 miles at times. With the 2-km spatial resolution (at satellite nadir) of the GOES-17 Infrared spectral bands, there was not a signature of this smaller-scale Boulder City dust plume in the 10.3-12.3 µm and 11.2-8.4 µm Brightness Temperature Difference products — however, this hazy plume was evident in the 0.5-km resolution (at satellite nadir) Visible imagery.

Time series plot of surface data at Boulder City Municipal Airport [click to enlarge]

Time series plot of surface data at Boulder City Municipal Airport [click to enlarge]

A comparison of 1-km resolution NOAA-19 AVHRR Visible (0.63 µm), Shortwave Infrared (3.8 µm) and Split Window (10.8-12.0 µm) images (below) provided a detailed view of the primary dust plume — and also exhibited a subtle signature of the smaller plume that reduced visibility at Boulder City KBVU. The small dust aerosols act as efficient reflectors of incoming solar radiation, therefore appearing warmer (darker) on the Shortwave Infrared image.

NOAA-19 AVHRR Visible (0.63 µm), Shortwave Infrared (3.8 µm) and Split Window (10.8-12.0 µm) images, with plots of 23 UTC surface reports [click to enlarge]

NOAA-19 AVHRR Visible (0.63 µm), Shortwave Infrared (3.8 µm) and Split Window (10.8-12.0 µm) images, with plots of 23 UTC surface reports [click to enlarge]

The GOES-17 and NOAA-19 images also showed that the larger dust plume moved across a section of Interstate 15 between Sloan and Jean; traffic cameras showed significant reductions in visibility along I-15 near Primm (along the California/Nevada border).

Fires in the Plains

April 8th, 2019 |

GOES-16 Shortwave Infrared (3.9 µm) and Fire Temperature product [click to play animation | MP4]

GOES-16 Shortwave Infrared (3.9 µm) and Fire Temperature product [click to play animation | MP4]

GOES-16 (GOES-East) Shortwave Infrared (3.9 µm) images and the corresponding GOES-16 Fire Temperature product (above) showed the thermal signatures of widespread fires across the Great Plains (primarily in the Flint Hills of Kansas and Oklahoma) on 08 April 2019. Although fairly small and often relatively brief, some of these fires become quite hot — exhibiting Fire Temperature values as high as 2762 K (or 4512ºF) southwest of Cottonwood, Kansas at 2011 UTC. These fires were typical Springtime prescribed burns and agricultural fields being cleared for planting.

One fire southwest of Salina, Kansas began to exhibit a prominent 3.9 µm thermal anomaly after 22 UTC, attaining a peak infrared brightness temperature of 95.6ºC (or 204ºF); a closer view of that fire is shown using GOES-16 Shortwave Infrared images along with Fire Temperature, Fire Area and Fire Power products (below). Note that during much of the time (for example, at 2221 UTC) there were no Fire Temperature, Fire Area or Fire Power values processed for the hottest 3.9 µm fire pixel — this is because the fire was producing a thick smoke plume, and the smoke-filled (on Visible imagery) hot pixel was flagged by the GOES Fire Detection and Characterization Algorithm (FDCA) Cloud Mask as a “cloudy pixel”. Beginning in May 2019, an updated algorithm will begin to produce the Fire Power parameter for all types of fire pixel (Processed fire, Saturated fire, Cloud-contaminated fire, and High/Medium/Low-probability fires), but the Fire Temperature and Fire Size parameters will only be available for the Processed fire category.

GOES-16 Shortwave Infrared (3.9 µm, upper left), Fire Temperature (upper right), Fire Area (lower left) and Fire Power (lower right) [click to play animation | MP4]

GOES-16 Shortwave Infrared (3.9 µm, upper left), Fire Temperature (upper right), Fire Area (lower left) and Fire Power (lower right) [click to play animation | MP4]

A sequence of MODIS and VIIRS Shortwave Infrared (3.7 µm) images from the Aqua, Suomi NPP and NOAA-20 satellites (below) showed a more detailed view of the fire thermal signatures (black to yellow to red enhancement) during the 1.5 hours between 1822 and 2001 UTC.

Sequence of MODIS and VIIRS Shortwave Infrared (3.7 µm) images from 1822-2001 UTC [click to enlarge]

Sequence of MODIS and VIIRS Shortwave Infrared (3.7 µm) images from 1822-2001 UTC [click to enlarge]

Most of the small fires did not produce particularly large smoke plumes, but the density of the fires led to a rather large pall of smoke over the region as seen in GOES-16 “Red” Visible (0.64 µm) images (below). Note the smoke plume emanating from the fire southwest of Salina, Kansas (as previously discussed). Most of the smoke was dispersed above the boundary layer — but the surface visibility was reduced by smoke at sites such as Coffeyville, Chanute and Eureka in southeastern Kansas and Bartlesville in northeastern Oklahoma.

GOES-16 "Red" Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

===== 09 April Update ====

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images [click to enlarge]

As some of the larger fires in southern Kansas continued burning into the night, their thermal signature could be seen in NOAA-20 VIIRS Shortwave Infrared (3.74 µm) image (darker gray to black pixels), along with their bright glow in the corresponding VIIRS Day/Night Band (0.7 µm) image at 0818 UTC or 3:18 am CDT (above). Note: the NOAA-20 images are incorrectly labeled as Suomi NPP.