Eruption of the Mount Pavlof volcano in Alaska

March 28th, 2016

Himawari-8 AHI Shortwave Infrared (3.9 µm) images [click to play animation]

Himawari-8 AHI Shortwave Infrared (3.9 µm) images [click to play animation]

A major eruption of the Mount Pavlof volcano on the Alaska Peninsula began shortly before 0000 UTC on 28 March, or 4:00 pm on 27 March Alaska time (AVO report), as detected by a thermal anomaly (or “hot spot”, yellow to red color enhancement) on Himawari-8 AHI Shortwave Infrared (3.9 µm) images (above). The hot spot decreased in size and intensity toward the later hours of the day, signaling a lull in the volcanic eruption.

It is interesting to note on a comparison of the 0000 UTC Himawari-8 and GOES-15 Shortwave Infrared (3.9 um) images the large difference in the magnitude of the thermal anomaly — even though the viewing angle was larger for Himawari-8, the superior spatial resolution (2 km at nadir, compared to 4 km with GOES-15) detected a hot spot with an Infrared Brightness Temperature (IR BT) that was 36.6 K warmer (below). The Infrared channels on the GOES-R ABI instrument will also have a 2 km spatial resolution.

Himawari-8 AHI (left) and GOES-15 Imager (right) 3.9 µm Shortwave Infrared images [click to enlarge]

Himawari-8 AHI (left) and GOES-15 Imager (right) 3.9 µm Shortwave Infrared images [click to enlarge]

With the aid of reflected light from the Moon (in the Waxing Gibbous phase, at 75% of Full), a nighttime view using the Suomi NPP VIIRS Day/Night Band (0.7 µm) from the SSEC RealEarth site (below) revealed the bright glow of the eruption, along with the darker (compared to adjacent meteorological clouds) volcanic ash cloud streaming northeastward. The corresponding VIIRS Shortwave Infrared (3.74 µm) image showed the dark black hot spot of the volcano summit.

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

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

The volcanic ash cloud continued moving in a northeastward direction, as seen in a sequence of GOES-15 Infrared Window (10.7 µm) and either Terra/Aqua MODIS or Suomi NPP VIIRS retrieved Volcanic Ash Height products from the NOAA/CIMSS Volcanic Could Monitoring site (below).

GOES-15 Infrared (10.7 µm) images, with Terra/Aqua MODIS and Suomi NPP VIIRS Ash Height products [click to play animation]

GOES-15 Infrared (10.7 µm) images, with Terra/Aqua MODIS and Suomi NPP VIIRS Ash Height products [click to play animation]

Due to the oblique satellite view angle, the shadow cast by the tall volcanic ash cloud was easily seen on the following early morning (Alaska time) Himawari-8 AHI Visible (0.64 µm) images (below). A closer view (courtesy of Dan Lindsey, RAMMB/CIRA) revealed overshooting tops and gravity waves propagating downwind of the eruption site.

Himawari-8 AHI Visible (0.64 um) images (click to play animation]

Himawari-8 AHI Visible (0.64 um) images (click to play animation]

A few select Pilot reports (PIREPs) are shown below, plotted on GOES-15 Infrared Window (10.7 µm) and Aqua MODIS Ash Height derived products. Numerous flights were canceled as the ash cloud eventually began to drift over Western and Interior Alaska (media report).

GOES-15 Infrared Window (10.7 um) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 um) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 um) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm) image, with METAR surface reports and Pilot reports [click to enlarge]

Aqua MODIS Ash Height product, with METAR surface reports and Pilot reports [click to enlarge]

Aqua MODIS Ash Height product, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 um), with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm), with METAR surface reports and Pilot reports [click to enlarge]

A comparison of Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm), and true-color Red/Green/Blue (RGB) images (below) showed the volcanic hot spot and the brown to tan colored ash cloud at 2141 UTC on 28 March. Significant ash fall (as much as 2/3 of an inch) was experienced at the village of Nelson Lagoon, located 55 miles northeast of Pavlof (media report).

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

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

A comparison of the 3 Himawari-8 AHI Water Vapor bands (7.3 µm, 6.9 µm and 6.2 µm) covering the first 14 hours of the eruption from 0000 to 1400 UTC is shown below. Note that volcanic plume was best seen on the 7.3 µm images, which indicated that it began to move over the coast of Western Alaska after around 0600 UTC; this is due to the fact that the 7.3 µm band is not only a “water vapor absorption” band, but is also sensitive to high levels of SO2 loading in the atmosphere (as was pointed out in this blog post).

Himawari-8 AHI Water Vapor 7.3 µm (left), 6.9 µm (center) and 6.2 µm (right) images [click to play animation]

Himawari-8 AHI Water Vapor 7.3 µm (left), 6.9 µm (center) and 6.2 µm (right) images [click to play animation]

Eruption of the Popocatépetl Volcano in Mexico

January 25th, 2016

Soumi NPP VIIRS true-color RGB images [click to enlarge]

Soumi NPP VIIRS true-color RGB images [click to enlarge]

The Popocatépetl Volcano in Mexico began erupting at 1546 UTC on 20 January 2016 (Washington VAAC message). The volcanic plume was evident on Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images on 23, 24, and 25 January, as viewed using the SSEC RealEarth web map server (above).

Nighttime images of Suomi NPP VIIRS Shortwave Infrared (3.9 µm), Longwave Infrared Window (11.45 µm), and Day/Night Band (0.7 µm) images at 0817 UTC on 25 January (below, courtesy of William Straka, SSEC) revealed the hot spot of the erupting volcano summit (orange pixels), and ample illumination from the Moon allowed the plume to be seen on the Day/Night Band image. The large areas of bright city lights from Mexico City and Pueblo (located northwest and southeast of Popocatépetl, respectively) are also very apparent on the Day/Night Band image.

Suomi NPP VIIRS Shortwave Infrared (3.9 µm), Longwave Infrared Window (11.45 µm), and Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.9 µm), Longwave Infrared Window (11.45 µm), and Day/Night Band (0.7 µm) images [click to enlarge]

A legacy product for use in the detection of volcanic ash plumes is the Infrared “Split-Window” (11-12 µm) brightness temperature difference product (below), which showed the plume streaming eastward to northeastward during the 24-25 January period.

Terra/Aqua MODIS and Suomi NPP VIIRS Infrared "Split Window" (11-12 µm) Brightness Temperature Difference product images [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS Infrared “Split Window” (11-12 µm) Brightness Temperature Difference product images [click to enlarge]

Taking advantage of the multi-spectral imagery available from the MODIS and VIIRS instruments on the Terra/Aqua ans Suomi NPP satellites, quantitative products can be derived such as Ash Height, Ash Loading, Ash Effective Radius, and Ash Probability from the NOAA/CIMSS Volcanic Coud Monitoring (below).

Terra/Aqua MODIS and Suomi NPP VIIRS Volcanic Ash Height product [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS Volcanic Ash Height product [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS Volcanic Ash Loading product [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS Volcanic Ash Loading product [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS Volcanic Ash Effective Radius product [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS Volcanic Ash Effective Radius product [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS Volcanic Ash Probability product [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS Volcanic Ash Probability product [click to enlarge]

Mount Rinjani volcanic ash plume

November 4th, 2015

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

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

The Mount Rinjani volcano in Indonesia began a period of eruptions on 25 October 2015; the ash plume became very apparent on Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images from RealEarth on 03 and 04 October (above). The volcanic ash disrupted flights at Denpasar Airport in Bali (the red dot at the southern tip of the island) for several days.

A GOES-R volcanic ash height product (derived using Himawari-8 AHI data) from the SSEC Volcanic Cloud Monitoring site indicated that the plume reached heights of 10 km (dark blue color enhancement) at times during the 03-04 October period (below).

Himawari-8 Volcanic Ash Height product [click to play animation]

Himawari-8 Volcanic Ash Height product [click to play animation]

McIDAS-V images of Suomi NPP VIIRS Day/Night Band (0.7 µm), near-IR (1.6 µm), shortwave IR (3.74 µm), and IR (11.45 µm) images (below, courtesy of William Straka, SSEC) showed the hot spot and nighttime glow of the summit of the Rinjani volcano at 1733 UTC on 04 November.

Suomi NPP VIIRS Day/Night Band (0.7 µm), near-IR (1.6 µm), shortwave IR (3.74 µm), and IR (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm), near-IR (1.6 µm), shortwave IR (3.74 µm), and IR (11.45 µm) images [click to enlarge]

Eruption of the Cotopaxi volcano in Ecuador

August 14th, 2015

GOES-13 visible (0.63 µm) images [click to play animation]

GOES-13 visible (0.63 µm) images [click to play animation]

GOES-13 visible (0.63 µm) images (above; click to play animation) displayed distinct dark-gray ash plumes from 2 separate daytime eruptions of the Cotopaxi volcano in Ecuador on 14 August 2015 (there was also an initial eruption that occurred during the preceding nighttime hours). The asterisk near the center of the images marks the location of the volcano summit. Volcanic ash fall was observed in the capitol city of Quito (station identifier SEQU, located about 50 km or 30 miles north of the volcano), and some flights were diverted due to the volcanic ash cloud.

The corresponding GOES-13 infrared (10.7 µm) images (below; click image to play animation) showed that cloud-top IR brightness  temperatures were as cold a -53º C (orange color enhancement) at 1915 UTC.

GOES-13 infrared (10.7 µm) images [click to play animation]

GOES-13 infrared (10.7 µm) images [click to play animation]

The volcanic cloud features were also easily tracked on GOES-13 water vapor (6.5 µm) images (below; click image to play animation). In fact, note how the signature in the water vapor imagery is more distinctly seen for a longer period of time than on the 10.7 µm infrared imagery.

 GOES-13 water vapor (6.5 µm) images [click to play animation]

GOES-13 water vapor (6.5 µm) images [click to play animation]

The tan-colored volcanic ash cloud was also evident on Aqua MODIS and Suomi NPP VIIRS true-color Red/Green/Blue (RGB) imagery (below), as viewed using the SSEC RealEarth web map server.

Aqua MODIS true-color images [click to enlarge]

Aqua MODIS true-color images [click to enlarge]

Suomi NPP VIIRS true-color image [click to enlarge]

Suomi NPP VIIRS true-color image [click to enlarge]

A comparison of Suomi NPP VIIRS visible (0.64 µm) and infrared (11.45 µm) images is shown below (courtesy of William Straka, SSEC). The coldest cloud-top IR brightness temperature was -72.7º C.

Suomi NPP VIIRS visible (0.64 µm) and infrared (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS visible (0.64 µm) and infrared (11.45 µm) images [click to enlarge]