Eruption of Bogoslof in Alaska’s Aleutian Islands

May 28th, 2017 |

Himawari-8 Visible (0.64 µm, left) and Infrared Window (10.4 µm, right) images, with hourly surface and ship reports plotted in yellow [click to play animation]

Himawari-8 Visible (0.64 µm, left) and Infrared Window (10.4 µm, right) images, with hourly surface and ship reports plotted in yellow [click to play animation]

The Bogoslof volcano in Alaska’s Aleutian Islands erupted around 2216 UTC on 29 May 2017. A comparison of Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images (above; MP4) showed the volcanic cloud as it drifted north/northeastward.

A very oblique view of the volcanic cloud was captured by Korean COMS-1 satellite at 2315 UTC (below).

COMS-1 Visible (0.67 µm) images, with surface observations plotted in yellow [click to enlarge]

COMS-1 Visible (0.67 µm) images, with surface observations plotted in yellow [click to enlarge]

Himawaari-8 false-color images from the NOAA/CIMSS Volcanic Cloud Monitoring site (below) revealed the initial signature of a volcanic cloud — however, this signature became less distinct after about 02 UTC on 29 May.

Himawari-8 false-color RGB images [click to play animation]

Himawari-8 false-color RGB images [click to play animation]

A different type of Himawari-8 false-color imagery (below) makes use of the 8.5 µm spectral band, which can help to infer the presence of sulfur dioxide within a volcanic cloud feature. A similar 8.4 µm band is available from the ABI instrument on the GOES-R series of satellites.

Himawari-8 false-color images [click to play animation]

3Himawari-8 false-color images [click to play animation]

A blend of Himawari-8 Infrared Window (10.4 µm) and radiometrically-retrieved Ash Cloud Height is shown below; the maximum ash cloud height was generally in the 10-12 km (33,000-39,000 feet above sea level) range (dark blue color enhancement). A volcanic ash signal was no longer apparent after 2320 UTC — this was likely due to enhanced ash particle removal via water (both liquid and ice) related processes.

Himawari-8 Infrared Window (10.4 µm) images and Ash Cloud Height retrievals [click to play animation]

Himawari-8 Infrared Window (10.4 µm) images and Ash Cloud Height retrievals [click to play animation]

A DigitalGlobe WorldView image at 2234 UTC (below) provided remarkable detail of the Bogoslof volcanic cloud shortly after the eruption began.


Eruption of Kambalny volcano in Kamchatka, Russia

March 25th, 2017 |

Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images [Click to play animation]

Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images [Click to play animation]

The Kambalny volcano in far southern Kamchatka, Russia erupted around 2120 UTC on 24 March 2017. A Himawari-8 “Target Sector” was positioned over that region — providing rapid-scan (2.5-minute interval) imagery — as seen in a 2-panel comparison of AHI Visible (0.64 µm) and Infrared Window (10.4 µm) data covering the first 7 hours of the eruption (above). Ash plume infrared brightness temperatures quickly became -40ºC and colder (bright green enhancement).

Himarari-8 false-color RGB images [click to play animation]

Himarari-8 false-color RGB images [Click to play animation]

Himawari-8 false-color Red/Green/Blue (RGB) images from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) showed the ash plume drifting south-southwestward during the subsequent nighttime hours. It is interesting to note the formation and subsequent northwestward motion of numerous contrails (darker green linear features) across the region, due to the close proximity of a major Tokyo flight corridor.

True-color RGB images from Terra MODIS, Suomi NPP VIIRS and Aqua MODIS, viewed using RealEarth (below) revealed the long ash plume during the late morning and early afternoon on 25 March. The dark signature of ash fall onto the snow-covered terrain was evident on the Terra and Aqua images, just west of the high-altitude ash plume.

Terra MODIS, Suomi NPP VIIRS and Aqua MODIS true-color RGB images [Click to enlarge]

Terra MODIS, Suomi NPP VIIRS and Aqua MODIS true-color RGB images [Click to enlarge]

26 March Update: a closer view of Terra MODIS true-color images from 25 and 26 March (below) showed that the perimeter of the darker gray surface ash fall signature had fanned out in both the west and east directions.

Terra MODIS truecolor RGB images from 25 and 26 March, with arrows indicating the perimeter of surface ash fall signatures on each day [Click to enlarge]

Terra MODIS truecolor RGB images from 25 and 26 March, with arrows indicating the perimeter of surface ash fall signatures on each day [Click to enlarge]

Eruption of Alaska’s Bogoslof volcano

December 22nd, 2016 |

Himawari-8 0.64 µm (left) and GOES-15 0.63 µm (right) Visible images [click to play animation]

Himawari-8 0.64 µm (left) and GOES-15 0.63 µm (right) Visible images [click to play animation]

Following a short-lived eruption on 21 December, the Bogoslof volcano in the eastern Aleutian Island chain of Alaska erupted again at about 0110 UTC on 22 December 2016. The volcanic cloud could be seen moving north/northeastward away from Bogoslof (denoted by the yellow * symbol) on Himawari-8 and GOES-15 Visible images (above). The higher spatial and temporal resolution from Himawari-8 (0.5 km at nadir, with images every 10 minutes) provided a more detailed view of the cloud feature compared to GOES-15 (with 1.0 km resolution at nadir, and images every 15 minutes); however, the ABI instrument on the GOES-R series will have an identical 0.5 km resolution Visible band. Another Himawari-8 Visible image animation is available from RAMMB.

Multispectral Red/Green/Blue (RGB) images from the NOAA/CIMSS Volcanic Cloud Monitoring site (below) displayed a signal of the volcanic cloud during the ~2.5 hours following the onset of the eruption — since this particular RGB combination uses the 3.9 µm Shortwave Infrared band, the volcanic cloud feature appeared as darker shades of magenta during the first few images while reflected solar illumination was present before sunset.

Himawari-8 false-color RGB images [click to play animation]

Himawari-8 false-color RGB images [click to play animation]

Another variant of RGB images (below) uses the 8.5 µm “cloud top phase” band, which is also sensitive to SO2 absorption; in this case, the appearance of the volcanic cloud feature was dominated by shades of yellow, indicating high levels of SO2.

Himawari-8 false-color RGB images [click to play animation]

Himawari-8 false-color RGB images [click to play animation]

A comparison of the 3 Himawari-8 water vapor bands (below) showed that a strong signature of the volcanic cloud was seen on the lower-tropospheric 7.3 µm band; this was due to the fact that the 7.3 µm band is also sensitive to elevated levels of SO2 loading in the atmosphere (which was also noted at the bottom of this Mount Pavlof eruption blog post). These same 3 water vapor bands (Upper-level, Mid-level and Lower-level) will be available from the GOES-R series ABI instrument.

Himawari-8 6.2 µm (top), 6.9 µm (middle) and 7.3 µm (bottom) Water Vapor images [click to play animation]

Himawari-8 6.2 µm (top), 6.9 µm (middle) and 7.3 µm (bottom) Water Vapor images [click to play animation]

A closer view using Himawari-8 false-color images (below) includes a magenta polygon surrounding the volcanic cloud soon after the onset of the eruption — this is an example of an experimental automated volcanic eruption alerting system. According to Michael Pavolonis (NOAA/NESDIS), “Using our automated cloud object tracking algorithm, the eruption produced a cloud at 01:30 UTC that was about 19 deg C colder than the background imaged by Himawari-8 at 01:20 UTC.  Taking into account the pixel size, background cloud cover, and time interval between successive images, the 19 deg C change is about an 11 standard deviation outlier relative to a very large database of meteorological clouds.  The vertical growth anomaly calculation is the basis of one the components of our experimental automated volcanic eruption alerting system”.

Himawari-8 false-color images, with a polygon surrounding the volcanic cloud [click to enlarge]

Himawari-8 false-color images, with a polygon surrounding the volcanic cloud [click to enlarge]

The creation of RGB images such as those shown above will be possible from the GOES-R series of satellites (beginning with GOES-16), since the ABI instrument has the 8.4 µm and 12.3 µm bands that are not available from the current generation of GOES imager instruments.

Additional satellite images of this event are available from NWS Anchorage.

25-year anniversary of the 1991 Mount Pinatubo eruption

June 15th, 2016 |

GMS-4 Infrared Window (11.5 µm) images [click to play animation]

GMS-4 Infrared Window (11.5 µm) images [click to play animation]

During the first 2 weeks of June 1991 the Mount Pinatubo volcano on the island of Luzon in the Philippines began to produce a series of eruptions, culminating in the climactic eruption beginning at 0227 UTC on 15 June. An animation of 5-km resolution GMS-4 Infrared Window (11.5 µm) images (above) spans the period from 1831 UTC on 12 June to 1831 UTC on 16 June, and showed the very large volcanic cloud following the 15 June eruption (the animation pauses at the 0230 UTC image on 15 June — just after the time of the major eruption). Also evident in the imagery was the westward movement of what became Category 3 Typhoon Yunya (known locally in the Philippines as Diding) toward Luzon. A larger-scale version of the animation is available here.

A closer view of the GMS-4 Infrared Window (11.5 µm) images (below) revealed interesting characteristics of the volcanic plume which penetrated the tropopause (which was at an air temperature of around -83º C, according to nearby rawinsonde reports) during the 3-8 hours following the onset of the 0227 UTC eruption. Note the initial appearance of a small area of very warm IR cloud-top IR brightness temperatures (-21.6º C at 0631 UTC, and -25.7º C at 0730 UTC) which then blossomed outward and became a westward-moving stratospheric plume that was notably warmer than the majority of the cold volcanic cloud canopy (which exhibited IR brightness temperatures in the -80º to -90º C range, denoted by the violet to yellow color enhancement).

GMS-4 Infrared Window (11.5 µm) images [click to enlarge]

GMS-4 Infrared Window (11.5 µm) images [click to enlarge]

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NOAA-10 AVHRR Infrared Window (10.8 µm), Visible (0.91 µm) and Shortwave Infrared (3.7 µm) images [click to enlarge]

NOAA-10 AVHRR Infrared Window (10.8 µm), Visible (0.91 µm) and Shortwave Infrared (3.7 µm) images [click to enlarge]

A higher-resolution (1.1-km) view of the post-eruption cloud was provided by NOAA-10 AVHRR images at 1034 UTC on 15 June (above). Even though it was just past sunset over the Philippines, the narrow stratospheric plume could be seen towering above the canopy of the main volcanic cloud (the plume was at a high enough altitude — estimated at a maximum of 40 km (reference 1 | reference 2) — to still be illuminated by sunlight). The summit of Pinatubo is located 8.7 miles/14 km west-southwest of what was then Clark Air Force Base (station identifier RPLC). On the 10.8 µm Infrared Window image, cloud-top gravity waves could be seen propagating radially outward from the overshooting top located above the volcano (which exhibited a minimum IR brightness temperature of -86º C, violet color enhancement). Note the much warmer IR brightness temperatures (as warm as -31º C, green color enhancement) associated with the stratospheric plume just off the west coast of Luzon. A closer view is available here.

About 10 hours prior to the climactic eruption, a volcanic ash cloud from one of the earlier eruptions was captured by NOAA-10 AVHRR images at 2329 UTC on 14 June (below). Around this same time it can be seen that Yunya was making landfall as a minimal-intensity typhoon along the eastern coast of Luzon. A closer view is available here.

NOAA-10 AVHRR Infrared Window (10.8 µm), Visible (0.91 µm) and Shortwave Infrared (3.7 µm) images [click to enlarge]

NOAA-10 AVHRR Infrared Window (10.8 µm), Visible (0.91 µm) and Shortwave Infrared (3.7 µm) images [click to enlarge]