25-year anniversary of the 1991 Mount Pinatubo eruption

June 15th, 2016

GMS-4 Infrared Window (11.5 µm) images [click to play animation]

GMS-4 Infrared Window (11.5 µm) images [click to play animation]

During the first 2 weeks of June 1991 the Mount Pinatubo volcano on the island of Luzon in the Philippines began to produce a series of eruptions, culminating in the climactic eruption beginning at 0227 UTC on 15 June. An animation of 5-km resolution GMS-4 Infrared Window (11.5 µm) images (above) spans the period from 1831 UTC on 12 June to 1831 UTC on 16 June, and showed the very large volcanic cloud following the 15 June eruption (the animation pauses at the 0230 UTC image on 15 June — just after the time of the major eruption). Also evident in the imagery was the westward movement of what became Category 3 Typhoon Yunya (known locally in the Philippines as Diding) toward Luzon. A larger-scale version of the animation is available here.

A closer view of the GMS-4 Infrared Window (11.5 µm) images (below) revealed interesting characteristics of the volcanic plume which penetrated the tropopause (which was at an air temperature of around -83º C, according to nearby rawinsonde reports) during the 3-8 hours following the onset of the 0227 UTC eruption. Note the initial appearance of a small area of very warm IR cloud-top IR brightness temperatures (-21.6º C at 0631 UTC, and -25.7º C at 0730 UTC) which then blossomed outward and became a westward-moving stratospheric plume that was notably warmer than the majority of the cold volcanic cloud canopy (which exhibited IR brightness temperatures in the -80º to -90º C range, denoted by the violet to yellow color enhancement).

GMS-4 Infrared Window (11.5 µm) images [click to enlarge]

GMS-4 Infrared Window (11.5 µm) images [click to enlarge]

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NOAA-10 AVHRR Infrared Window (10.8 µm), Visible (0.91 µm) and Shortwave Infrared (3.7 µm) images [click to enlarge]

NOAA-10 AVHRR Infrared Window (10.8 µm), Visible (0.91 µm) and Shortwave Infrared (3.7 µm) images [click to enlarge]

A higher-resolution (1.1-km) view of the post-eruption cloud was provided by NOAA-10 AVHRR images at 1034 UTC on 15 June (above). Even though it was just past sunset over the Philippines, the narrow stratospheric plume could be seen towering above the canopy of the main volcanic cloud (the plume was at a high enough altitude — estimated at a maximum of 40 km (reference 1 | reference 2) — to still be illuminated by sunlight). The summit of Pinatubo is located 8.7 miles/14 km west-southwest of what was then Clark Air Force Base (station identifier RPLC). On the 10.8 µm Infrared Window image, cloud-top gravity waves could be seen propagating radially outward from the overshooting top located above the volcano (which exhibited a minimum IR brightness temperature of -86º C, violet color enhancement). Note the much warmer IR brightness temperatures (as warm as -31º C, green color enhancement) associated with the stratospheric plume just off the west coast of Luzon. A closer view is available here.

About 10 hours prior to the climactic eruption, a volcanic ash cloud from one of the earlier eruptions was captured by NOAA-10 AVHRR images at 2329 UTC on 14 June (below). Around this same time it can be seen that Yunya was making landfall as a minimal-intensity typhoon along the eastern coast of Luzon. A closer view is available here.

NOAA-10 AVHRR Infrared Window (10.8 µm), Visible (0.91 µm) and Shortwave Infrared (3.7 µm) images [click to enlarge]

NOAA-10 AVHRR Infrared Window (10.8 µm), Visible (0.91 µm) and Shortwave Infrared (3.7 µm) images [click to enlarge]

GOES-3 is being decommissioned

May 27th, 2016
GOES3_VIS_1545_18MAY1980

GOES-3 Visible Image from 18 May 1980 at 1545 UTC (Click to enlarge)

GOES-3 started service on 16 June 1978 and was the operational GOES-West satellite until the late 1980s. Having lost imaging capabilities, it started a second long life as a communications satellite; GOES-3 is currently the oldest operating satellite. Decommissioning will begin on 8 June and run for 15 days. If final decommissioning happens as planned on 23 June, GOES-3’s service life will be 38 years, 7 days.

GOES-3’s arguably most famous imagery occurred during the eruption of Mount St. Helens on 18 May 1980, shown above (click here for an animation of the eruption, courtesy of Barry Roth, SSEC; Tim Schmit, NOAA/ASPB also provided longer visible animations: MP4 | animated GIF).

A comparison of GOES-3 Visible (0.65 µm) and Infrared Window (11.5 µm) images, below, showed that a large portion of the volcanic cloud exhibited IR brightness temperatures of -60º C (dark red color enhancement) or colder as the feature moved rapidly eastward during the first 10 hours following the eruption. It is interesting to note that an “enhanced-V” or cold/warm (-65º/-47º C) thermal couplet signature was evident on the initial 1545 UTC Infrared image (zoom), as the volcanic ash cloud rapidly rose to an estimated altitude of 12 to 16 miles (20 to 27 km) above sea level.

GOES-3 0.65 µm Visible (top) and 10.7 µm Infrared Window (bottom) images [click to play animation]

GOES-3 0.65 µm Visible (top) and 11.5 µm Infrared Window (bottom) images [click to play animation]

Some early examples of full disk GOES-3 images (on 20 November 1978) are shown below, courtesy of Tim Schmit, NOAA/ASPB.

GOES-3 Visible (0.65 µm) and Infrared Window (11.6 µm) images [click to enlarge]

GOES-3 Visible (0.65 µm) and Infrared Window (11.6 µm) images [click to enlarge]

A look back at the Blizzard of 02-04 January 1999

January 1st, 2016

GOES-8 Water Vapor (6.5 µm) images [click to play MP4 animation]

GOES-8 Water Vapor (6.5 µm) images [click to play MP4 animation]

The evolution of the Blizzard of 02-04 January 1999 — which impacted large portions of the Midwest and Great Lakes regions of the US, as well as parts of eastern Canada — was captured by GOES-8 Water Vapor (6.5 µm, 8-km resolution) images (above; also available as a 61-Mbyte animated GIF). On 01 January, the water vapor image signature of a shortwave trough over New Mexico and Texas could be seen, which began to intensify and move northeastward; at the same time, the signature of another shortwave trough began moving southeastward across eastern Montana and the Dakotas. Energy from this northern shortwave appeared to phase with that of the southern shortwave late on 02 January into early on 03 January, helping the storm to further intensify.

GOES-8 Infrared (10.7 µm, 4-km resolution) images (below; also available as a 111-Mbyte animated GIF) showed that cloud-top IR brightness temperatures began to cool into the -50 to -60º C range (orange to red color enhancement) over large portions of the Upper Midwest and Great Lakes regions during the day on 02 January. As the bulk of the storm energy moved northeastward over Canada on 03-04 January, evidence of clouds associated with a TROugh of Warm air ALoft (TROWAL) persisted across parts of Minnesota and Wisconsin.

GOES-8 Infrared (10.7 µm) images [click to play MP4 animation]

GOES-8 Infrared (10.7 µm) images [click to play MP4 animation]

Even though some patches of clouds remained in the aftermath of the blizzard on 04 January, the extent of snow cover across much of the eastern US could be seen — from northern Arkansas to Minnesota, and from the Dakotas and Nebraska to Ohio — on GOES-8 Visible (0.65 µm, 1-km resolution) images (below; also available as a 15 Mbyte animated GIF). Bands of lake effect snow were also evident over each of the Great Lakes, as very cold arctic air flowed across the ice-free waters in the wake of the storm.

GOES-8 Visible (0.65 µm) images [click to play MP4 animation]

GOES-8 Visible (0.65 µm) images [click to play MP4 animation]

In the Upper Midwest region, storm total snowfall amounts included: 28.0 inches in South Haven, Michigan; 26.8 inches in Plymouth, Indiana; 23.0 inches in Dalton, Wisconsin; and 19.6 inches a Chicago O’Hare, Illinois. Chicago recorded 18.6 inches of snow on 02 January — their largest single-day snowfall on record. In Canada, Toronto, Ontario’s Pearson International Airport was closed by the storm, where 16.0 inches of snow fell. With deep snow cover and a cold post-storm arctic air mass in place, the all-time record low temperature for the state of Illinois (-36º F) was set at Congerville on 05 January.

Additional details on the January 1999 Blizzard can be found here and here.

40th Anniversary of the “Edmund Fitzgerald Storm”

November 10th, 2015

NOAA-4 daytime and nighttime Infrared composites [click to enlarge]

NOAA-4 daytime and nighttime Infrared composites [click to enlarge]

Today marks the 40-year anniversary of the powerful Great Lakes storm that was responsible for the sinking of the SS Edmund Fitzgerald (which occurred on 10 November 1975). The image composites (above, courtesy of Jean Phillips, Schwerdtfeger Library) were constructed from daytime and nighttime overpasses of the NOAA-4 polar-orbiting satellite, and show the large cloud shield of the storm moving northeastward from the Great Lakes into eastern Canada during the 10-11 November 1975 period. The rapidly-intensifying nature of the storm can seen by comparing the 12 UTC surface analyses on 09 November and 10 November.

Since the first operational geostationary weather satellites (SMS-1 and SMS-2) were relatively new back in 1975, the CIMSS Regional Assimilation System (CRAS) model was utilized to generate synthetic Infrared (IR) satellite images to provide a general idea of what the satellite imagery might have looked like for this intense storm. The 48-hour sequence of synthetic CRAS IR images (below) shows the evolution of the model-derived cloud features at 1-hour intervals.

CRAS model simulated Infrared imagery [click to enlarge]

CRAS model simulated Infrared imagery [click to enlarge]

Additional information about this Edmond Fitzgerald storm can be seen on this website and this lecture, as well as the NWS Marquette and this journal article.

A strong storm of similar character developed over the Upper Midwest and Great Lakes region on 9-11 November 1998. GOES-8 (GOES-East) Infrared (10.7 µm) and Water Vapor (6.7 µm) images of this 1998 storm are shown below (and are also available as YouTube videos). This storm set all-time minimum barometric pressure records for the state of Minnesota, with 962 mb (28.43″) recorded at Albert Lea and Austin in southern Minnesota. On the cold side of the storm, up to 12.5 inches of snow fell at Sioux Falls in southeastern South Dakota. Wind gusts were as high as 64 mph in Minnesota and 94 mph in Wisconsin.

GOES-8 Infrared (10.7 µm) images [click to play MP4 animation]

GOES-8 Infrared (10.7 µm) images [click to play MP4 animation]

GOES-8 Water Vapor (6.7 µm) images [click to play MP4 animation]

GOES-8 Water Vapor (6.7 µm) images [click to play MP4 animation]