PyroCumulonimbus cloud in Texas

May 11th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, bottom) images, with hourly plots of surface reports [click to play MP4 animation]

A large pyroCumulonimbus (pyroCb) cloud developed from the Mallard Fire in the Texas Panhandle on 11 May 2018, aided by warm temperatures and strong winds ahead of an approaching dryline (surface analyses).  1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the large thermal anomaly or “hot spot” (red 3.9 µm pixels) and the rapid development of  the pyroCb cloud beginning shortly after 1900 UTC. Cloud-top infrared brightness temperatures cooled to -60 ºC — the tropopause temperature on the 00 UTC Amarillo sounding — by around 2130 UTC. On the Shortwave Infrared imagery, note the relatively warm (darker gray) appearance of the pyroCb cloud top — a characteristic signature of pyroCb anvils due to enhanced reflection of solar radiation off of smaller cloud-top particles.

4-panel comparisons of Suomi NPP VIIRS Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images at 1936 UTC and 2029 UTC (below) revealed that the maximum differences between 3.74 µm and 11.45 µm cloud-top infrared brightness temperatures — at the same location on the pyroCb anvil — were 86ºC (+26ºC and -59ºC at 1936 UTC) and 91.5ºC (+27.5ºC and -63ºC at 2029 UTC).

Suomi NPP VIIRS Visible (0.64 µm), Near-Infrared

Suomi NPP VIIRS Visible (0.64 µm, upper left), Near-Infrared “Snow/Ice” (1.61 µm, upper right), Shortwave Infrared (3.74 µm, lower left) and Infrared Window (11.45 µm, lower right) images at 1936 UTC and 2029 UTC [click to enlarge]

Lightning was detected from portions of the smoke plume, as well as the core of the pyroCb thunderstorm.

After dark, the thermal signature of the Mallard Fire was also apparent on GOES-16 Near-Infrared “Cloud particle size” (2.24 µm) imagery (below).

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Cloud particle size” (2.24 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, bottom) images, with hourly plots of surface reports [click to play MP4 animation]

===== 12 May Update =====

Terra MODIS True-color and False-color images [click to enlarge]

Terra MODIS True-color and False-color images [click to enlarge]

In a comparison of 250-meter resolution Terra MODIS True-color and False-color Red-Green-Blue (RGB) images from the MODIS Today site (above), the Mallard Fire burn scar was evident in the False-color. Both images showed a smoke plume from ongoing fire activity, which was drifting northward across the Texas Panhandle.

The corresponding Terra MODIS Land Surface Temperature product (below) indicated that LST values within the burn scar were as high as 137ºF (darker red enhancement), in contrast to values around 100ºF adjacent to the burn scar.

Terra MODIS Land Surface Temperature product [click to enlarge]

Terra MODIS Land Surface Temperature product [click to enlarge]

Eruptions of Kilauea in Hawai’i

May 5th, 2018 |

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

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

Heightened seismic activity of the Kilauea volcano on the Big Island of Hawai’i had been ongoing since April 2018, but increased further in early May leading to a series of minor eruptions (Hawaiian Volcano Observatory | USGS) — and GOES-15 (GOES-West) Shortwave Infrared (3.9 µm) images (above) showed the nearly persistent thermal anomaly or “hot spot” (dark black to red enhancement) during the 03-05 May period. Among the numerous earthquakes, the strongest was an M6.9 which occurred at 2233 UTC on 04 May.

A nighttime image of Suomi NPP VIIRS Day/Night Band (0.7 µm) data viewed using RealEarth (below) revealed the bright glow from Kilauea, and also from the Leilani Estates subdivision where several fissure vents had opened (forcing some evacuations).

Suomi NPP VIIRS Day.Night Band (0.7 µm) images, with island boundary and Google Maps labels [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) images, with the island boundary and Google Maps labels [click to enlarge]

A comparison of Suomi NPP VIIRS Day/Night Band images from 03 May and 04 May (below) showed the before/after difference in the bright signal emitted by the fissure vents near Leilani Estates.

Suomi NPP VIIRS Day/Night Band (0.7 µm) images from 03 May and 04 May [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) images from 03 May and 04 May [click to enlarge]

===== 06 May Update =====

Eruptions of fissure vents became more continuous in the Leilani Estates subdivision on 06 May. A comparison of GOES-15 Visible and Shortwave Infrared images (below) showed a long volcanic plume streaming southwestward, with robust thermal anomaly activity at the plume source.

http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2018/05/G15_VIS_SWIR_HI_06MAY2018_960x640_B12_2018126_201500_0002PANELS_00002.GIF

GOES-15 Visible (0.63 µm, left) and Shortwave Infrared (3.9 µm, right) images, with hourly plots of surface reports [click to play animation | MP4]

An Aqua MODIS True-color Red-Green-Blue (RGB) image (below) provided a more detailed view of the volcanic plume at 0007 UTC on 07 May. Note the cluster of red thermal anomalies in the vicinity of the Leilani Estates subdivision (the source of the plume).

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

Aqua MODIS True-color RGB image, with VIIRS thermal anomalies plotted in red [click to enlarge]

Valley fog and mountain snow in the Catskills of New York

May 1st, 2018 |

As pointed out by NWS Binghamton, valley fog and higher-elevation snow cover was apparent on GOES-16 (GOES-East) Visible imagery in the Catskills of southeastern New York on the morning of 01 May 2018. A closer view comparing GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (below) showed the dissipation of the valley fog, followed by the melting of the snow cover in higher terrain (snowfall amounts of up to 3-4 inches fell in the area on 29 April). The Snow/Ice imagery was helpful in discriminating between the brighter valley fog features and the darker snow cover.

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Near-Infrared “Snow/Ice” (1.61 µm, right) images, with hourly plots of surface reports [click to play animation | MP4]

A 250-meter resolution Terra MODIS True-color Red-Green-Blue (RGB) image acquired from the SSEC Direct Broadcast ground station (below) showed the remaining snow cover over the Catskills (near the center of the image) at 1539 UTC.

Terra MODIS True-color image [click to enlarge]

Terra MODIS True-color image [click to enlarge]

Refinery Explosion and Fire in Superior WI

April 26th, 2018 |

GOES-16 ABI “Red Visible” (0.64 µm) from 1532-2027 UTC on 26 April 2018 (Click to enlarge)

Explosions at an oil refinery in Superior WI on 26 April 2018 (news link) produced a black plume of smoke visible in the GOES-16 “Red Visible” Band, the highest resolution (0.5 km at nadir) band on GOES-16. The plume is first visible at about 1717 UTC, and it then streams southeastward over northwest Wisconsin. Areas immediately downwind of the refinery were evacuated due to air quality concerns.

The explosion and subsequent fire was not sufficiently hot to be detected by the shortwave infrared 3.9 µm channel on GOES-16. However, the smoke plume is obvious in this animation, cooler than the background by 3-4ºC, and yellow in the enhancement chosen.

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Near-Infrared “Vegetation” (0.86 µm, right) images [click to animate]

The dark smoke plume was also evident on Near-Infrared “Vegetation” (0.86 µm) images (above), aided by the additional contrast between the dark plume and the lighter gray appearance of the land surface.

GOES-16 Natural Color images [click to animate]

GOES-16 Natural Color RGB images [click to animate]

The GOES-16 Natural Color Red-Green-Blue (RGB) product (above) was also useful for identifying and tracking the smoke plume.

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

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

250-meter resolution Aqua MODIS True Color and False Color images from the MODIS Today site (above) provided a detailed view of the smoke plume at 1842 UTC. In the False Color image, snow cover and lake ice appear as shades of cyan.