Eruption of Mount Veniaminof on the Alaska Peninsula

November 21st, 2018 |
GOES-17

GOES-17 “Red” Visible (0.64 µm) and Split Window Difference (10.3-12.3 µm) images [click to play MP4 animation]

* GOES-17 images posted here are preliminary and non-operational *

Following an eruption of Mount Veniaminof on 21 November 2018, 1-minute Mesoscale Domain Sector GOES-17 “Red” Visible (0.64 µm) and Split Window Difference (10.3-12.3 µm) images (above) showed the volcanic ash plume drifting southeastward over the Gulf of Alaska. During the period 1947-2323 UTC the plume was seen to grow to a length of 200 miles from the volcano summit. Note in the Visible imagery that the 2625 ft (800 m) volcano acted as a barrier to the northwesterly boundary layer winds to create a cloud-free “notch” immediately downwind of Veniaminof.

NOAA-20 VIIRS True Color RGB images viewed using RealEarth (below) highlighted the light brown color of the ash plume.

NOAA-20 VIIRS True Color RGB images [click to enlarge]

NOAA-20 VIIRS True Color RGB images [click to enlarge]

A sequence of retrieved Ash Probability, Ash Height and Ash Loading (source) derived from Terra/Aqua MODIS and Suomi NPP VIIRS data (below) indicated high probabilities of ash content, height values primarily in the 4-6 km range and ash loading exceeding 4 g/m3 at times.

Terra/Aqua MODIS and Suomi NPP VIIRS Ash Probability, Ash Height and Ash Loading images [click to play animation | MP4]

Terra/Aqua MODIS and Suomi NPP VIIRS Ash Probability, Ash Height and Ash Loading images [click to play animation | MP4]

 

Eruption of Volcán de Fuego in Guatemala

November 19th, 2018 |

GOES-16 Upper-level (6.2 µm, top), Mid-level (6.9 µm, center) and Low-level (7.3 µm, bottom) Water Vapor images [click to play animation | MP4]

GOES-16 Upper-level (6.2 µm, top), Mid-level (6.9 µm, center) and Low-level (7.3 µm, bottom) Water Vapor images [click to play animation | MP4]

Following several days of unrest, there was a moderate eruption of Volcán de Fuego in Guatemala beginning around 0630 UTC on 19 November 2018. GOES-16 (GOES-East) Upper-level (6.2 µm), Mid-level (6.9 µm) and Low-level (7.3 µm) Water Vapor images (above) displayed a signature of the volcanic plume, which drifted slowly northward and eastward for several hours. Since the 7.3 µm spectral band is also affected by SO2 absorption, the longer-lasting signal in the Low-level Water Vapor imagery suggests the plume contained SO2 as well as ash (since the 7.3 µm band is also sensitive to SO2 absorption).

A GOES-16 multiispectral Ash/Dust Cloud Height product from the NOAA/CIMSS Volcanic Cloud Monitoring site (below) indicated that the ash reached a maximum height of 7-8 km in the general vicinity of the summit between 1100-1200 UTC. A low-altitude plume of ash was seen drifting westward at heights of 1-5 km.

GOES-16 Ash Height product [click to play animation | MP4]

GOES-16 Ash/Dust Cloud Height product [click to play animation | MP4]

Along the southern coast of Guatemala, a 1400 UTC METAR from San Jose (MGSJ) reported a surface visibility of 5 statute miles with Volcanic Ash in the vicinity (VCVA) as the current weather type (below). At that time, the GOES-16 Split Window (10.3-12.3 µm) Brightness Temperature Difference was highlighting  concentrations of middle-tropospheric volcanic ash (yellow enhancement) farther inland closer to the volcano.

GOES-16 Split Window difference (10.3-12.3 µm) image, with METAR surface reports [click to enlarge]

GOES-16 Split Window difference (10.3-12.3 µm) image, with METAR surface reports [click to enlarge]

Alaska: a thunderstorm, single digits and a volcano

September 25th, 2018 |

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (above) captured an unusually late thunderstorm that produced small hail at Anchorage PANC (surface observations) on 24 September 2018. The coldest cloud-top infrared brightness temperature was -53.8ºC, which was colder than the -46.3ºC tropopause temperature on the 00 UTC Anchorage sounding. This particular thunderstorm (Anchorage averages only 1-2 per year) even featured a wall cloud:



In far northeastern Alaska, snow cover across the North Slope and Brooks Range was evident in a sequence of Suomi NPP VIIRS Visible (0.64 µm) images (below). Since there were also areas of low cloud present (both north and south of the primary snow cover), the VIIRS Shortwave Infrared (3.74 µm) images could be used to discriminate between these low clouds — whose supercooled water droplets were effective reflectors of solar radiation, making then appear warmer or darker gray — and the cloud-free areas of snow cover.

Sequence of 4 Suomi NPP VIIRS Visible (0.64 µm) and Shortwave Infrared (3.74 µm) images [click to enlarge]

Sequence of 4 Suomi NPP VIIRS Visible (0.64 µm) and Shortwave Infrared (3.74 µm) images [click to enlarge]

The presence of this snow cover aided strong nighttime radiational cooling as a ridge of high pressure moved over the North Slope (surface analyses), and on the following morning temperatures dropped as low as 4ºF (the temperature later reached 3ºF at Toolik Lake):

Finally, along the Alaska Peninsula, Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images revealed the bright glow and hot thermal signature of the ongoing eruption of Mount Veniaminof at 1204 UTC and 1344 UTC (below).

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 1204 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 1204 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 1344 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 1344 UTC [click to enlarge]

Coincidentally, on this day GOES-17 began a test of Mode 6 operation which performs a Full Disk scan every 10 minutes. Although the Alaska Peninsula was on the extreme northwest limb of the Full Disk scan, Veniaminof’s thermal anomaly or “hot spot” (darker black pixels) could still be detected and monitored at 10 minute intervals using Shortwave Infrared (3.9 µm) imagery (below). However, an increase in layered cloud cover southeast of that area later in the day (in tandem with the extreme satellite view angle) eventually masked the warm thermal signature — a more direct view from overhead with Suomi NPP VIIRS still showed a very hot volcano summit (96.9ºC) at 2156 UTC.

GOES-17 Shortwave Infrared (3.74 µm) images [click to play animation | MP4]

GOES-17 Shortwave Infrared (3.74 µm) images [click to play animation | MP4]

Since there were no significant ash emissions from Mount Veniaminof on this day, no volcanic signature was evident on GOES-17 “Red” Visible (0.64 µm) imagery (below).

GOES-17

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

* GOES-17 images shown here are preliminary and non-operational *

Eruption of the Sierra Negra volcano in the Galapagos

July 1st, 2018 |

GOES-16 False Color RGB images [click to play animation]

GOES-16 False Color RGB images [click to play animation]

GOES-16 (GOES-East) False Color Red-Green-Blue (RGB) images from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) showed another eruption of the Sierra Negra volcano on the Galapagos, which began late in the day on 01 July 2018. Since the volcanic plume was rich in SO2, it exhibited a cyan appearance in the RGB imagery.

As was demonstrated following the 26 June eruption, GOES-16 Low-level Water Vapor (7.3 µm) imagery (below) can also be used to initially track volcanic plumes that have high concentrations of SO2 (since this spectral band is also sensitive to SO2 absorption).

GOES-16 Low-level Water Vapor (7.3 µm) images [click to play animation | MP4]

GOES-16 Low-level Water Vapor (7.3 µm) images [click to play animation | MP4]