VIIRS « CIMSS Satellite Blog

Eruption of Mount Shishaldin in Alaska

January 19th, 2020 | Scott Bachmeier

Topography along with Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images at 1323 UTC [click to enlarge]

Following two days of increasing seismicity, Mount Shishaldin began a period of more intense eruptive activity around 0930 UTC on 19 January 2020 — a comparison of topography along with Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images at 1323 UTC (above) displayed a distinct thermal anomaly (cluster of red 3.74 µm pixels) and a volcanic cloud moving east-southeastward.

Comparisons of Shortwave Infrared and Infrared Window images from Suomi NPP VIIRS and GOES-17 ABI (below) revealed a parallax shift that is inherent with geostationary imagery at high latitudes.

Comparison of Shortwave Infrared images from Suomi NPP VIIRS (3.74 um) and GOES-17 ABI (3.9 um) [click to enlarge]

Comparison of Shortwave Infrared images from Suomi NPP VIIRS (3.74 µm) and GOES-17 ABI (3.9 µm) [click to enlarge]

Comparison of Infrared Window images from Suomi NPP VIIRS (11.45 µm) and GOES-17 ABI (10.35 µm) [click to enlarge]

A toggle between GOES-17 parallax correction vectors and magnitudes for cloud top heights of 15,000 feet (4.5 km) and 30,000 feet (9.1 km) are shown below — the amount of northwestward volcanic cloud displacement between the Suomi NPP and GOES-17 Infrared images roughly matched the 16 km (or 10 mile) value for a 15,000 foot cloud top in that region of the Full Disk. Later advisories listed the maximum ash height at 20,000-30,0000 feet.

GOES-17 parallax correction vectors (green) and magnitudes (km, red) [click to enlarge]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) Split Cloud Top Phase (11.2 – 8.4 µm) images (below) displayed an increasing volcanic ash signal (negative values, darker blue to violet enhancement) beginning around 01 UTC on 20 January. Some light ash fall was reported at False Pass, Alaska.

GOES-17 Split Cloud Top Phase (11.2 - 8.4 um) images [click to play animation | MP4]

GOES-17 Split Cloud Top Phase (11.2 – 8.4 µm) images [click to play animation | MP4]

10-minute images of GOES-17 radiometrially retreived Ash Height from the NOAA/CIMSS Volcanic Cloud monitoring site (below) indicated that the bulk of the ash plume existed within the 2-6 km altitude range.

GOES-17 Ash Height product [click to play animation | MP4]

In corresponding GOES-17 False Color Red-Green-Blue (RGB) images (below), the volcanic plume exhibited shades of red/magenta/pink — the characteristic signature of an ash-laden cloud.

GOES-17 False Color RGB [click to play animation | MP4]

Posted in GOES-17, Red-Green-Blue (RGB) images, Suomi NPP, VIIRS, Volcanic activity | No Comments »

Eruption of the Taal Volcano in the Philippines

January 12th, 2020 | Scott Bachmeier

Himawari-8 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.4 µm, right) images [click to play animation | MP4]

The Taal Volcano erupted in the Philippines around 0850 UTC on 12 January 2020. JMA Himawari-8 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.4 µm) images (above) displayed the volcanic cloud during the initial 3 hours post-eruption. Note the presence of a pronounced “warm wake” (red enhancement) downwind (north) of the summit of Taal — this appeared to be an Above-Anvil Cirrus Plume (AACP), as seen in a toggle between the Visible and Infrared images at 1910 UTC (below).

Himawari-8 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.4 µm) images at 1910 UTC [click to enlarge]

The warmest Himawari-8 10.4 µm brightness temperatures within the Above-Anvil Cirrus Plume were around -60ºC (red enhancement), which corresponded to approximately 21 km on data from 3 rawinsonde sites in the Philippines (Legaspi, Mactan and Laoag) (below).

Plots of rawinsonde data from Legaspi, Mactan and Laoag in the Philippines [click to enlarge]

The TROPOMI detected SO2 at altitude of 20km on 13 January:

The SO2 signal from #Taal detected by #TROPOMI on 2020-01-13 has an altitude of up to 20km. #SO2LH. @tropomi @DLR_en @ESA_EO pic.twitter.com/x6nstNRWUw

— TROPOMI SO2 (@DlrSo2) January 13, 2020

A longer animation of Himawari-8 Infrared imagery revealed the intermittent presence of the warm wake feature until about 1400 UTC. The coldest 10.4 µm cloud-top brightness temperature was -89.7ºC.

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

A large-scale view of Himawari-8 Infrared images (below) showed that the volcanic cloud was advected a great distance north-northeastward.

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

A toggle between NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (below) showed the volcanic cloud at 1649 UTC.

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1648 UTC (credit: William Straka, CIMSS) [click to enlarge]

In a sequence of Split Window Difference (11-12 µm) images (Terra MODIS, NOAA-20 VIIRS and Suomi NPP VIIRS) from the NOAA/CIMSS Volcanic Cloud Monitoring site (below), there was only a subtle ash signature (blue enhancement) immediately downwind of the Taal summit — due to the large amount of ice within the upper portion of the volcanic cloud, the infrared spectral ash signature was significantly masked.

Split Window Difference (11-12 um) images from Terra MODIS, NOAA-20 VIIRS and Suomi NPP VIIRS [click to enlarge]

Split Window Difference (11-12 µm) images from Terra MODIS, NOAA-20 VIIRS and Suomi NPP VIIRS [click to enlarge]

Of interest was the fact that Manila International Airport (RPLL) reported a thunderstorm at 15 UTC — there was a large amount of lightning produced by Taal’s volcanic cloud.

#TaalEruption as seen from @VaisalaGroup merged total lightning (NLDN and GLD) 15-min plots. This lapse is about 15 hours long and lightning activity has quieted since. ?#TaalEruption2020 #TaalVolcano @COweatherman pic.twitter.com/kkxjztq9KU

— William Churchill (@kudrios) January 13, 2020

Volcanic eruption at #TaalVolcano with AMAZING #volcano #lightning display. Remind me later to get counts. Data from @VaisalaGroup #GLD360. #VaisalaDigital #AMS2020 @janinekrippner @C_MarieSmith @volcaniclastic @simoncarn @CorCima pic.twitter.com/vYpgPJRoGC

— Ch?is Vagas|?y (@COweatherman) January 12, 2020

If you’re mesmerized by the steamy #Taal eruption plume and wondering why it’s creating so much #VolcanicLightning, you’re not alone. Here’s a micro-crash course on the physics of volcanic thunderstorms for non-specialists. Thanks to @joshibob_ for the incredible footage! (1/14) pic.twitter.com/CCl6zw56RZ

— Alexa Van Eaton (@volcaniclastic) January 13, 2020

===== 14 January Update =====

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

2 days after the eruption, the leading edge of Taal’s SO2-rich volcanic plume (brighter shades of yellow over areas of cold clouds) began to appear within the far western view of GOES-17 (GOES-West) Full Disk SO2 Red-Green-Blue (RGB) images (above), about 1000 miles southeast of Japan. There were also some thin filaments of SO2 (brighter shades of white over warm ocean areas) moving southward, about 1500 miles west of Hawai’i.

Volcanic SO2 cloud from #TaalVolcano is moving further East towards Alaska. #TROPOMI @TROPOMI @Sentinel5p @ESA_EO @DLR_en @BIRA_IASB #SO2LH pic.twitter.com/Brp4Iig0PV

— TROPOMI SO2 (@DlrSo2) January 14, 2020

Posted in GOES-17, Himawari-8, MODIS, NOAA-20, Red-Green-Blue (RGB) images, Suomi NPP, Terra, VIIRS, Volcanic activity | No Comments »

Another outbreak of pyrocumulonimbus clouds in Australia

January 4th, 2020 | Scott Bachmeier

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

Following a multi-day outbreak in late December 2019, Australian bushfires flared up again across far eastern Victoria and far southeastern New South Wales (along and ahead of a cold frontal passage) on 04 January 2020. A JMA Himawari-8 Target Sector was positioned over that region, providing images at 2.5-minute intervals — “Red” Visible (0.64 µm) images displayed the large smoke plumes with embedded pyro-convection, while Shortwave Infrared (3.9 µm) images revealed the widespread fire thermal anomalies or “hot spots” (clusters of red pixels).

Himawari-8 Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.4 µm) images (below) showed the development of 2 pyrocumulonimbus (pyroCb) clouds — the first over southern New South Wales west of Cooma (station identifier YCOM), and the second to the southwest of YCOM (near the border between Victoria and New South Wales). The second pyroCb eventually exhibited cloud-top infrared brightness temperature (IRBT) values of -70ºC and colder (purple pixels). To be classified as a pyroCb, a deep convective cloud must be generated by a large/hot fire, and eventually exhibit cloud-top 10.4 µm IRBTs of -40ºC and colder (thus assuring the heterogeneous nucleation of all supercooled water droplets to ice crystals within the thunderstorm anvil).

Himawari-8 Shortwave Infrared (3.9 µm, top) and “Clean” Infrared Window (10.4 µm, bottom) images [click to play animation | MP4]

An aircraft flying very near or through one of these pyroCb clouds experienced severe turbulence:

On 4th Jan a @Qantas flight between Melbourne – Canberra flew through a PyroCB: A large, energetic, thunderstorm triggered by the #AustralianFires, causing severe turbulence: https://t.co/VvrsStWXK9

Here’s how it looked from space. Storm encounter was at approx. 07:47 UTC. pic.twitter.com/shuDaCk1ti

— SatWx Aviation (@SatWx_Aviation) January 6, 2020

Farther to the north, another pyroCb developed near Nowra, New South Wales (YSNW) — which briefly exhibited a -40ºC cloud-top IRBT at 0319 UTC, but then re-intensified around 08 UTC (below).

Himawari-8 Shortwave Infrared (3.9 µm, top) and “Clean” Infrared Window (10.4 µm, bottom) images [click to play animation | MP4]

In a sequence of VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 um) images from NOAA-20 and Suomi NPP as viewed using RealEarth (below), the Nowra pyroCb was less ambiguous during the 03-04 UTC time period — and the aforementioned pair of pyroCbs straddling the border between Victoria and New South Wales were also evident.

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

===== 06 January Update =====

GOES-16 Natural Color RGB images + Smoke Detection derived product [click to play animation | MP4]

On 06 January, GOES-16 (GOES-East) Natural Color RGB images (above) displayed the hazy signature of high-altitude smoke (originating from previous episodes of Australian fires) over parts of Chile and Argentina — and the corresponding GOES-16 Smoke Detection derived product flagged much of this feature as “High Confidence” smoke (red).

In addition, GOES-17 (GOES-West) True Color RGB images created using Geo2Grid (below) showed a dense pall of smoke over the South Pacific Ocean (northeast of New Zealand). This was smoke from the 04 January outbreak of fires.

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

===== 08 January Update =====

GOES-17 True Color RGB images, 05-08 January [click to play animation | MP4]

Full Disk GOES-17 True Color RGB images from the AOS site (above) showed the slow eastward transport of a dense pall of smoke (hazy shades of tan to light brown) across the South Pacific Ocean during the 05-08 January period.

Late in the day, GOES-17 True Color images also showed a small area of smoke drifting southward across the coast of Antarctica (below).

GOES-17 True Color images [click to play animation | MP4]

This was confirmed by the OMPS Aerosol Index product (below), which displayed a small lobe becoming detached from one of the larger smoke features crossing the South Pacific Ocean.

Suomi NPP OMPS Aerosol Index composites, 04-08 January (credit: Colin Seftor, SSAI)

Posted in Antarctic, Aviation, Fire detection, GOES-16, GOES-17, Himawari-8, NOAA-20, RealEarth, Red-Green-Blue (RGB) images, Suomi NPP, VIIRS | No Comments »

Multi-day outbreak of pyrocumulonimbus clouds across southeastern Australia

December 29th, 2019 | Scott Bachmeier

Himawari-8 Shortwave Infrared (3.9 µm, top) and Longwave Infrared Window (10.4 µm, bottom) images [click to play animation | MP4]

JMA Himawari-8 Shortwave Infrared (3.9 µm) and Longwave Infrared Window (10.4 µm) images (above) showed a large bushfire (dark black to red pixels in the 3.9 µm imagery) in far southeastern Victoria, Australia — which quickly burned its way to the coast and produced 3 distinct pulses of pyrocumulonimbus (pyroCb) clouds on 29 December 2019. To be classified as a pyroCb, the deep convective cloud must be generated by a large/hot fire (in this case, the Cann River fire complex), and eventually exhibit cloud-top 10.4 µm infrared brightness temperatures of -40ºC and colder (assuring the heterogeneous nucleation of all supercooled water droplets to ice crystals).

The coldest cloud-top 10.4 µm infrared brightness temperature was -62.6ºC (darker green pixels) at 1650 UTC. According to rawinsonde data from Melbourne (below), this corresponded to an altitude near 13 km.

Plots of rawinsonde data from Melbourne, Australia [click to enlarge]

The long/narrow thermal anomaly of the hot bushfire — which burned southwestward all the way to the coast — was outlined in dark black pixels on VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP, as viewed using RealEarth (below).

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

===== 30 December Update =====

Himawari-8 Shortwave Infrared (3.9 µm, top) and Longwave Infrared Window (10.4 µm, bottom) images [click to play animation | MP4]

A Himawari-8 Target Sector was positioned over southeastern Australia beginning at 2312 UTC on 29 December, providing images at 2.5-minute intervals — a comparison of Shortwave Infrared and Longwave Infrared Window imagery (above) revealed the formation of several additional pyroCb clouds as southeastern Victoria bushfires continued to grow in number and size. During the daytime, pyroCb cloud tops will appear warmer (darker gray) than those of conventional thunderstorms in the 3.9 µm imagery, due to enhanced reflection of solar radiation off the smaller ice crystals found in the pyroCb anvil. Development of the multiple deep convective pyroCb clouds on this day may have been aided by forcing for ascent provided by an approaching cold front and mid-tropospheric trough, along with favorable upper-tropospheric jet streak dynamics.

The coldest Himawari-8 cloud-top 10.4 µm brightness temperature on 30 December was -73.15ºC at 13:24:41 UTC (violet pixel near the coast); this was 5ºC colder than the coldest temperature of -68.1ºC — at an altitude of 15 km — on 12 UTC rawinsonde data from Melbourne (below). During the 12-hour period between the 2 soundings, the coded tropopause ascended from a height of 13.1 km (-63.7ºC) at 00 UTC to 14.2 km (-67.5ºC) at 12 UTC.

Plots of rawinsonde data from Melbourne, Australia at 00 UTC (yellow) and 12 UTC (cyan) [click to enlarge]

In a toggle between VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP is shown (below), a large pyroCb cloud was seen moving eastward away from the bushfires.

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

===== 31 December Update =====

Suomi NPP VIIRS Day/Night Band, Shortwave Infrared, Near-Infrared & Active Fire Product images at 1455 UTC on 31 December (credit: William Straka, CIMSS) [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.75 µm and 4.05 µm), Near-Infrared (1.61 µm and 2.25 µm) & Active Fire Product images at 1455 UTC on 31 December (credit: William Straka, CIMSS) [click to enlarge]

Suomi NPP VIIRS Day/Night Band, Shortwave Infrared, Near-Infrared & Active Fire Product images (above) showed nighttime signatures of the widespread bushfires across Victoria and New South Wales at 1455 UTC on 31 December (or 1:55 am local time on 01 January). In the town of Mallacoota, about 4000 people were forced to evacuate their homes and take shelter along the coast (media report). The surface air temperature at Mallacoota Airport briefly increased to 49ºC (120ºF) at 8:00 am local time as the fires approached (below).

Plot shows temperature recorded at #Mallacoota Airport earlier this morning. https://t.co/Qc5Nzwhqr4 Stay up to date @CFA_Updates @vicemergency pic.twitter.com/1eOKky0oAd

— Bureau of Meteorology, Victoria (@BOM_Vic) December 30, 2019

A sequence of daily Aqua MODIS True Color RGB images with an overlay of VIIRS Fire Radiative Power showed the fires and smoke during the 29-31 December period (below).