Ulawun volcano erupts in Papau New Guinea

June 26th, 2019 |

Himawari-8 Visible (0.64 µm, left), Shortwave Infrared (3.9 µm, center) and Infrared Window (10.4 µm, right) images [click to play animation | MP4]

Himawari-8 Visible (0.64 µm, left), Shortwave Infrared (3.9 µm, center) and Infrared Window (10.4 µm, right) images [click to play animation | MP4]

The Ulawun volcano erupted just after 0430 UTC on 26 June 2019 — a comparison of Himawari-8 Visible (0.64 µm), Shortwave Infrared (3.9 µm) and Infrared Window (10.4 µm) images (above) showed the thermal anomaly (yellow to red 3.9 µm pixels) preceding the eruption and the development of a well-defined umbrella cloud after the eruption. The coldest cloud-top infrared brightness temperature was -83.6ºC in conjunction with a prominent overshooting top at 0600 UTC. Note the eastward-moving cloud material that originated from this overshooting top — judging from Merauke/Mopah, Indonesia rawinsonde data (plot | data), the westerly winds required for such transport existed in the stratosphere at altitudes of 20-24 km. The pocket of warmer cloud-top 10.4 µm brightness temperatures associated with this stratospheric cloud material was the warmest at (-57.2ºC) at 0640 UTC (which, with the adjacent -82.7ºC overshooting top, created a cold/warm couplet whose magnitude was 25.5ºC). In addition, concentric gravity waves propagating outward across the volcanic cloud top were evident on the imagery.

Himawari-8 Infrared Window images (below) showed that the volcanic cloud dissipated fairly quickly. The eastward drift of the stratospheric cloud material also became difficult to follow after a couple of hours — even in Low-level Water Vapor (7.3 µm) imagery (which is also sensitive to SO2 absorption).

Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

Himawari-8 False Color RGB imagery along with radiometrically retrieved Ash Height, Ash Effective Radius and Ash Loading products (below) revealed a volcanic cloud characterized by high ash loading of large particles, having height values in the 16-20 km range (with a maximum height of 22 km).

False Color RGB (top left), Ash Height (top right), Ash Effective Radius (bottom left) and Ash Loading (bottom right) [click to play animation | MP4]

False Color RGB (top left), Ash Height (top right), Ash Effective Radius (bottom left) and Ash Loading (bottom right), courtesy of Mike Pavolonis, NOAA/NESDIS [click to play animation | MP4]

An oblique view of of the Ulawun volcanic cloud was provided by GOES-17 “Red” Visible (0.64 µm) images (below). This view accentuated the vertical extent of overshooting tops, and the large solar angle helped to highlight the cloud-top gravity waves. The 3-dimensional aspect of the two distinct eruption pulses along with the westward-drifting stratospheric plume were a bit more obvious in the GOES-17 images.

GOES-17 "Red" Visible <em>(0.64 µm)</em> images [click to play animation | MP4]

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

Eruption of the Raikoke volcano in the Kuril Islands

June 21st, 2019 |

Himawari-8 False Color RGB images [click to play animation | MP4]

Himawari-8 False Color RGB images [click to play animation | MP4]

For the first time since 1924, a major eruption of the Raikoke volcano occurred around 1800 UTC on 21 June 2019. Himawari-8 False Color Red-Green-Blue (RGB) images from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) showed — via the brighter yellow areas — that a large portion of the volcanic plume was rich in both ash and sulfur dioxide (SO2). The Tokyo VAAC estimated the maximum ash height to be 43,000 feet (~13 km) above ground level — and CALIPSO CALIOP data indicated a maximum ash height around 12 km shortly after 02 UTC on 22 June (between 45-50º N latitude and 159-161º E longitude).

A comparison of an Aqua MODIS False Color RGB image with the corresponding Ash Height, Ash Loading and Ash Effective Radius retrieved products at 0310 UTC on 22 June (below) indicated maximum ash height values of 18-20 km (black pixels) immediately downwind of the eruption site. Maximum Himawari-8 Ash Height values were in the 16-18 km range.

Aqua MODIS False Color RGB, Ash Height, Ash Loading and Ash Effective Radius at 0310 UTC on 22 June [click to enlarge]

Aqua MODIS False Color RGB image with Ash Height, Ash Loading and Ash Effective Radius retrieved products [click to enlarge]

In a comparison of Himawari-8 Upper-level (6.2 µm), Mid-level (6.9 µm) and Low-level (7.3 µm) Water Vapor images (below), since the 7.3 µm spectral band is also sensitive to SO2 absorption, those images showed a good signature of the leading filament of volcanic SO2 as it was transported east-southeastward over the North Pacific Ocean.

Water Vapor images from Himawari-8: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

Water Vapor images from Himawari-8: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

Similarly, the GOES–17 (GOES-West) Low-level Water Vapor (7.3 µm) images also showed the filament of volcanic SO2 that was being drawn into the circulation of a Gale Force Low south of the Aleutian Islands. As a result, the Anchorage VAAC issued aviation Volcanic Ash Advisories that covered large areas of the North Pacific Ocean and southern Bering Sea; they continued to estimate the maximum ash height to be 43,000 feet. Around 16 UTC on 22 June, CALPSO CALIOP data sampled a small portion of the ash at an altitude near 17 km (between 45-50º N latitude, 155-157º W longitude).

Water Vapor images from GOES-17: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

Water Vapor images from GOES-17: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth are shown below at approximately 01 UTC, 02 UTC and 03 UTC on 22 June. The combination of True Color and Infrared imagery indicated that volcanic ash was present a multiple altitudes.

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP at 01, 02 and 03 UTC on 22 June [click to enlarge]

Due to the highly-oblique satellite viewing angle of GOES-17, multiple Raikoke eruption pulses of significant vertical extent were clearly evident in GOES-17 “Red” Visible (0.64 µm) images (below).

GOES-17

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

A somewhat less oblique view from the west was provided by the NSMC FY-2G satellite (below).

NSMC FY-2G Visible (0.73 µm) images [click to play animation | MP4]

NSMC FY-2G Visible (0.73 µm) images [click to play animation | MP4]

Himawari-8 “Red” Visible (0.64 µm) images (below) provided another interesting view of the multiple eruption pulses — and since the eruption began around 5 AM local time, long early morning shadows were cast by the initial bursts of tall volcanic clouds. A faster animation revealed shock waves propagating radially outward from the eruption site.

Himawari-8

Himawari-8 “Red” Visible (0.64 µm) images [click to play animation | MP4]

Incidentally, an astronaut aboard the International Space Station took a photo of the volcanic cloud at 2246 UTC on 21 June — and the two Visible images that bracket that time (2240 and 2250 UTC) from GOES-17 and Himawari-8 are shown below.

Photo taken by an astronaut on the International Space Station [click to enlarge]

Photo taken by an astronaut on the International Space Station at 2246 UTC [click to enlarge]

GOES-17 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

GOES-17 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

Himawari-8 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

Himawari-8 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

===== 23 June Update =====

Himawari-8 False Color RGB images [click to play MP4 animation]

Himawari-8 False Color RGB images [click to play MP4 animation]

A 2-day animation of 10-minute Himawari-8 False Color images (above) showed the ash- and SO2-rich volcanic plume (brighter shades of yellow) eventually being transported northeastward across the western Aleutian Islands and circulating cyclonically over the Bering Sea. Similarly, this volcanic cloud transport was also seen in the corresponding GOES-17 False Color imagery.

===== 24 June Update =====

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB imagery (above) continued to show a signature of the volcanic cloud (brighter shades of yellow) from the Raikoke eruption over a large portion of the Bering Sea on 24 June. Volcanic ash advisories were issued for flight altitudes as high as 40,000 feet — and a pilot report of SO2 over the Bering Sea at 47,000 feet was received at 1822 UTC (below).

GOES-17 SO2 RGB, Split Clout Top Phase (11.2-8.4 µm) and Dust RGB images, with a pilot report of SO2 [click to enlarge]

GOES-17 SO2 RGB, Split Clout Top Phase (11.2-8.4 µm) and Dust RGB images, with a pilot report of SO2 [click to enlarge]

===== 25 June Update =====

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB images (above) showed the persistent signature of the SO2-rich volcanic cloud as much of it remained within the circulation of a quasi-stationary low pressure system in the Bering Sea.

An interesting Pilot Report north of the Aleutians at 36,000 feet (below) noted thin grey-colored layers below the altitude of the aircraft. GOES-17 Air Mass RGB images showed a subtle brown/tan plume — could this have been a thin filament of ash from the Raikoke eruption that was drawn into the circulation of the Bering Sea low?

GOES-17 SO2 RGB, Air Mass RGB, Dust RGB and Split Cloud Top Phase (11.2-8.4 µm) images, with a 2008 UTC Pilot Report [click to enlarge]

GOES-17 SO2 RGB, Air Mass RGB, Dust RGB and Split Cloud Top Phase (11.2-8.4 µm) images, with a 2008 UTC Pilot Report [click to enlarge]

Another Pilot Report farther to the west at 2119 UTC (below) was close to the southern edge of the GOES-17 SO2 signatures, but no sulphur odor was reported; however, they did note the presence of an apparent ash layer south of Shemya in the western Aleutian Islands.

GOES-17 SO2 RGB and Split Cloud Top Phase (11.2-8.4 µm)  images, with a 2119 UTC Pilot Report [click to enlarge]

GOES-17 SO2 RGB and Split Cloud Top Phase (11.2-8.4 µm) images, with a 2119 UTC Pilot Report [click to enlarge]

Asian dust entrained into a midlatitude cyclone

May 12th, 2019 |

True Color RGB images from MODIS (Terra) and VIIRS (NOAA-20 and Suomi NPP) [click to enlarge]

True Color RGB images from MODIS (Terra) and VIIRS (NOAA-20 and Suomi NPP) [click to enlarge]

True Color Red-Green-Blue (RGB) images from the MODIS instrument (on the Terra satellite) and the VIIRS instrument (on the NOAA-20 and Suomii NPP satellites) as viewed using RealEarth (above) revealed a tan-colored swirl of dust that had been lofted from the surface and entrained into the circulation of a midlatitude cyclone along the Mongolia/China border on 12 May 2019.

A sequence of MODIS/VIIRS True Color RGB images from Terra and Suomi NPP on 10, 11 and 12 May (below) showed the initial signature of surface-based blowing dust appearing in the Kumul and Jiuquan areas of northwestern China on 11 May, before it became wrapped into the circulation of the aforementioned midlatitude cyclone on 12 May.

True Color RGB images from MODIS (Terra) and VIIRS (Suomi NPP) [click to enlarge]

True Color RGB images from MODIS (Terra) and VIIRS (Suomi NPP) [click to enlarge]

Surface analyses at 3-hour intervals (source), from 12 UTC on 11 May to 00 UTC on 13 May (below) illustrated the strong pressure gradient between a large dome of high pressure over Mongolia and a developing midlatitude cyclone along the Mongolia/China border on 11 May — strong surface winds generated by this pressure gradient initially caused the blowing dust to begin in northwestern China.

Surface analyses at 3-hour intervals from 12 UTC on 11 May to 00 UTC on 13 May [click to enlarge]

Surface analyses at 3-hour intervals from 12 UTC on 11 May to 00 UTC on 13 May [click to enlarge]

JMA Himawari-8 Split Window Difference (10.4-12.3 µm) images (below) showed the signature of dust (yellow to cyan enhancement) moving eastward from the desert source region in northwestern China and becoming wrapped into the circulation of the midlatitude cyclone along the Mongolia/China border.

Himawari-8 Split Window Difference (10.4-12.3 µm) iimages [click to play animation |MP4]

Himawari-8 Split Window Difference (10.4-12.3 µm) images [click to play animation | MP4]

Ash fall streak from the Sheveluch volcano in Kamchatka

May 12th, 2019 |

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images, with topography [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images, with topography [click to enlarge]

In a comparison of Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 12 May 2019 (above), a dark volcanic ash fall streak was evident in the Visible image, which extended over 100 miles southward from the Sheveluch volcano on the Kamchatka Peninsula of Russia. This feature was a layer of volcanic ash that had been deposited on top of existing snow cover — note that most of the dark ash fall streak exhibited much cooler infrared brightness temperatures compared to the bare ground of the interior valley to the west (since the ash streak existed on top of a higher-altitude area of snow cover).

This ash fall streak was a result of an explosive eruption of the volcano over a month earlier, on 10 April — the volcanic ash plume could be seen moving southward in Himawari-8 Visible (0.64 µm) images (below).

Himawari-8

Himawari-8 “Red” Visible (0.64 µm) images [click to play animation | MP4]

An interesting aspect of this long-lived ash fall streak was that a portion of it was apparently covered by a layer of fresh snowfall at some point after the eruption — and a 7-day sequence of Suomi NPP VIIRS True Color Red-Green-Blue (RGB) images viewed using RealEarth (below) suggested that this layer of new snow was melting with the aid of the high May sun angle, gradually revealing more of the original length of the ash fall streak.

Suomi NPP VIIRS True Color RGB images, 06-12 May 2019 [click to play animation | MP4]

Suomi NPP VIIRS True Color RGB images, 06-12 May 2019 [click to play animation | MP4]

Note that there was another small volcanic plume moving south-southwestward from Sheveluch in the 09 May VIIRS True Color image — retrieved quantities of ash probability, height, loading and effective radius for this volcanic plume (source) are shown below.

Suomi NPP False Color, Ash Probability, Height, Loading and Effective Radius [click to enlarge]

Suomi NPP False Color, Ash Probability, Height, Loading and Effective Radius [click to enlarge]

This type of volcanic ash fall streak frequently occurs on the snow-covered Kamchatka Peninsula — here is an example from March 2013.

Thanks go out to Santiago Gassó for bringing this interesting feature to our attention.