Re-suspended volcanic ash from the Novarupta volcano in Alaska

September 29th, 2014
GOES-15 0.63 µm visible channel images (click to play animation)

GOES-15 0.63 µm visible channel images (click to play animation)

McIDAS images of GOES-15 0.63 µm visible channel data (above; click image to play animation) showed the hazy signature of a plume of re-suspended volcanic ash originating from the region of the Novarupta volcano in Alaska, moving southeastward over the Shelikof Strait toward Kodiak Island on 29 September 2014. The 1912 eruption of Novarupta left a very deep deposit of volcanic ash, which often gets lofted by strong winds in the early Autumn months before snowfall covers the ash (another example occurred on 22 September 2013). Surface winds gusted as high as 30 knots at regional reporting stations, with numerical models estimating terrain-enhanced winds as high as 40-50 knots over the Novarupta ash field.

An AWIPS II image of POES AVHRR 0.86 µm visible channel data (below) showed the ash plume at 22:46 UTC; a pilot report at 22:45 UTC indicated that the top of the ash plume was between 4000 and 6000 feet above ground level.

POES AVHRR 0.86 µm visible channel image, with METAR surface reports and Pilot reports (PIREPs)

POES AVHRR 0.86 µm visible channel image, with METAR surface reports and Pilot reports (PIREPs)

A sequence of 3 Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images from the SSEC RealEarth web map server (below) indicated that the re-suspended ash plume had been increasing in areal extent during that period.

Suomi NPP VIIRS true-color images from 27, 28, and 29 September

Suomi NPP VIIRS true-color images from 27, 28, and 29 September

A sequence of 4-panel products from the NOAA/CIMSS Volcanic Cloud Monitoring site (below) shows False-color images, Ash/dust cloud height, Ash/dust particle effective radius, and Ash/dust loading (derived from either Terra/Aqua MODIS or Suomi NPP VIIRS data).

4-panel MODIS/VIIRS products: False color image; Ash/dust cloud height; Ash/dust particle effective radius; Ash/dust loading

4-panel MODIS/VIIRS products: False color image; Ash/dust cloud height; Ash/dust particle effective radius; Ash/dust loading

Hat tip to Mark Ruminski (NOAA/NESDIS) for alerting us to this event.

Eruption of the Mount Ontake volcano in Japan

September 27th, 2014
Suomi NPP VIIRS true-color images on 27, 28, and 29 September

Suomi NPP VIIRS true-color images on 27, 28, and 29 September

The Mount Ontake volcano erupted on the main Japanese island of Honshu around 02:52 UTC (11:52 AM local time) on 27 September 2014. A sequence of three daily (27, 28, and 29 September) Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images from the SSEC RealEarth web map server (above) showed the volcanic plume drifting eastward then southeastward during that period. The ash plume disrupted air travel in some parts of Japan.

A comparison of pre-eruption (22 September) and post-eruption (28 September) VIIRS true-color images (below) revealed the light gray signature of thick volcanic ash covering the region around the summit of Mount Ontake. There was also a narrow volcanic plume streaming southeastward on the 28 September image.

22 September vs 28 September VIIRS true-color images

22 September vs 28 September VIIRS true-color images

The King Fire in California

September 19th, 2014
Suomi NPP VIIRS true-color images

Suomi NPP VIIRS true-color images

The King Fire began burning in central California (between Sacramento and Lake Tahoe) during the evening hours on 13 September 2014. A sequence of daily (12-19 September) Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images from the SSEC RealEarth web map server site (above) showed that as the prevailing southwesterly wind pattern switched to easterly on 19 September, there was a major change in the transport of smoke from the King Fire. The final image in the series zooms out to show how much of central California had become over-run with thick smoke.

A comparison of AWIPS-II images of Suomi NPP VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR image at 09:18 UTC or 2:18 AM local time (below) revealed the bright glow of the large fire complex, along with the large fire “hot spot” signature (black to yellow to red color enhancement).

Suomi NPP VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR images

Suomi NPP VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR images

Suomi NPP VIIRS 3.74 µm shortwave IR images during the overnight hours (just after 2 AM local time) on 17 and 18 September (below) showed the dramatic northeastward advance of the fire hot spot signature during that 24-hour period. Smoke from the fire was reducing the surface visibility to 3-4 miles as far to the northeast as Lovelock (KLOL) and Fallon (KNFL) in Nevada.

Suomi NPP VIIRS 3.74 µm shortwave IR images

Suomi NPP VIIRS 3.74 µm shortwave IR images

01 September, and no named tropical cyclones!

September 1st, 2014
Global composite of IR images, with tropical cyclone center points (click to play Animated GIF)

Global composite of IR images, with tropical cyclone center points (click to play Animated GIF)

It is rather rare to have no named tropical cyclones anywhere on the globe on the first day of September, but that was the case on 01 September 2014. A sequence of hourly global composite IR images from the SSEC RealEarth web map server (Animated GIF | MP4 movie file | YouTube video) showed the void of tropical activity — until Tropical Depression 5 formed late in the day in the Gulf of Mexico. This feature later became Tropical Storm Dolly early on 02 September.