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 Shortwave Infrared (3.9 µm) images (below) revealed a thermal anomaly or “hot spot” (yellow to red pixels) for several hours leading up to the 0430 UTC volcanic eruption.

Regarding the intensity of the thermal anomaly, a plot of volcano radiative power (VRP) and volcanic cloud longwave infrared brightness temperature (below) showed that the VRP exceeded 1 GW several hours prior to the formation of the eruption umbrella cloud.

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 generally in the 16-20 km range (with a maximum height of 22 km).

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 (with umbrella clouds at two different altitudes) along with the westward-drifting stratospheric plume were a bit more obvious in the GOES-17 images.

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A SpaceX Falcon Heavy rocket launch of the STP-2 mission occurred at 0630 UTC (2:30 am EDT) on 25 June 2019. 16-panel images showing all GOES-16 ABI spectral bands (above) revealed visible and thermal signatures — ranging from hot thermal signals of air superheated by the rocket exhaust (perhaps best seen in Water Vapor bands 8, 9 and 10) to signatures of the low-altitude exhaust plume cloud drifting slowly southward just off the Florida coast.

A magnified view of the 16-panel image at 0630 UTC is shown below. Note that there was a rocket signal seen in all 16 spectral bands — even the “Blue” Visible (0.47 µm) Channel 1, with a very subtle 0.1% reflectance value.

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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.

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.

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).

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.

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).

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

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.

?Sound on!
Hear #Raikoke's roar – Himawari satellite imagery of the June 21 #Raikoke #eruption (from @CIMSS_Satellite) with time-synched remote infrasound (from Robin Matoza at @ucsantabarbara) sped-up to be audible to humans. @C_MarieSmith @volcano_diana @CIDER_DeepEarth pic.twitter.com/wdeIZYBkn2

— Simon Carn (@simoncarn) June 29, 2019

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.

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

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 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).

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

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?

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.

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GOES-13 was taken out of storage on 19 June 2019 to begin a period of Image Navigation and Registration (INR) testing — the Satellite Data Services positioned a spare rooftop antenna to begin ingesting the GVAR data from the satellite (positioned over the Equator at 60.2º W longitude) . Visible images from 21 June are displayed above. According to NOAA: “With the established performance of NOAA’s new geostationary satellites, GOES-16 (as GOES-East) and GOES-17 (as GOES-West), and a healthy GOES-14 in reserve, NOAA can provide GOES-13 to the Air Force for their weather forecasting needs. After a check of the GOES-13 instruments, NOAA will operate the satellite on behalf of the Air Force during its remaining life span.”

A 5.5-hour animation of all five spectral bands of the GOES-13 Imager is shown below.

Water Vapor images from GOES-17 (GOES-West), GOES-15, GOES-16 (GOES-East) and GOES-13 (below) — all centered at Glasgow, Montana — showed the development of an anomalously-deep (for 21 June) mid-tropospheric cutoff low over eastern Montana. The images are displayed in the native projection of each satellite.

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

A 23.5-hour animation of all five spectral bands of the GOES-13 Imager is shown above, centered over Wisconsin.

GOES-13 Visible images centered near Cape Verde in western Africa (above) showed that the INR quality of GOES-13 was still very good.

===== 26 June Update =====

A test of GOES-13 Rapid Scan Operations (RSO)was conducted on 26 June — a sequence of Infrared Window and Visible images (above) revealed the presence of a Mesoscale Convective Vortex (MCV) off the US East Coast, following the dissipation of its parent nocturnal thunderstorm.

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