A comparison of 4-km resolution GOES-15 (GOES-West), GOES-14, and GOES-13 (GOES-East) 3.9 µm shortwave infrared images (above; click to play MP4 animation; also available as a 9.4 Mbyte animated GIF) showed the development and evolution of the “hot spot” (dark black to yellow to red color enhancement) associated with a small wildfire that formed near the border of Fergus and Petroleum counties in central Montana during the afternoon hours on 15 August 2015. With GOES-15 Routine Scan mode “SUB-CONUS” sectors, images were available up to 6 times per hour (at :00, :11, :15, :30, :41, and :45); with GOES-13 in Rapid Scan Operations (RSO) mode, images were available up to 8 times per hour (at :00, :07, :15, :25, :30, :37, :45, and :55). The GOES-14 satellite had been placed into Super Rapid Scan Operations for GOES-R (SRSO-R) mode, providing images at 1-minute intervals to emulate what will be available with mesoscale sectors from the ABI instrument on GOES-R.

For the central Montana wildfire, the first unambiguous signature of a darker black wildfire hot spot began to appear on each satellite after about 1945 UTC, with the first color-enhanced pixels (signifying a shortwave IR brightness temperature of 331.9 K) showing up on the 2026 UTC GOES-14 image. The hottest fire pixel  on the GOES-15 images was 336.5 K at 2130 UTC, while the hottest fire pixel on GOES-13 images was 329.8 K at 2125 UTC. From 2120 to 2130 UTC, the hottest GOES-14 fire pixels were 341.2 K (the saturation temperature of the 3.9 µm detectors on that satellite).

With the finer spatial resolution of the shortwave IR detectors on the polar-orbiting MODIS (1-km) and VIIRS (375-meter) instruments, a fire hot spot was first detected on the 1857 UTC VIIRS image (below).

View only this post Read Less

GOES-13 visible (0.63 µm) images (above; click to play animation) displayed distinct dark-gray ash plumes from 2 separate daytime eruptions of the Cotopaxi volcano in Ecuador on 14 August 2015 (there was also an initial eruption that occurred during the preceding nighttime hours). The asterisk near the center of the images marks the location of the volcano summit. Volcanic ash fall was observed in the capitol city of Quito (station identifier SEQU, located about 50 km or 30 miles north of the volcano), and some flights were diverted due to the volcanic ash cloud.

The corresponding GOES-13 infrared (10.7 µm) images (below; click image to play animation) showed that cloud-top IR brightness  temperatures were as cold a -53º C (orange color enhancement) at 1915 UTC.

The volcanic cloud features were also easily tracked on GOES-13 water vapor (6.5 µm) images (below; click image to play animation). In fact, note how the signature in the water vapor imagery is more distinctly seen for a longer period of time than on the 10.7 µm infrared imagery.

The tan-colored volcanic ash cloud was also evident on Aqua MODIS and Suomi NPP VIIRS true-color Red/Green/Blue (RGB) imagery (below), as viewed using the SSEC RealEarth web map server.

A comparison of Suomi NPP VIIRS visible (0.64 µm) and infrared (11.45 µm) images is shown below (courtesy of William Straka, SSEC). The coldest cloud-top IR brightness temperature was -72.7º C.

View only this post Read Less

A storage facility in Tianjin, China exploded shortly after 1500 UTC on 12 August 2015 (media story). Himawari-8, MTSAT-2 and COMS-1 all viewed the explosion that generated a strong thermal signature in the shortwave infrared band (3.75 µm – 3.9 µm). The animation above shows the benefit of Himawari-8’s speedier scanning mode: the smoke clouds that emanate from the explosion are easily traced, and data gaps when Full Disk images are being scanned (around 1800 UTC) are not present. Superior spatial resolution of Himawari-8 infrared channels (2-km, compared to 4-km for COMS-1 and MTSAT-2) means hotter brightness temperatures are sensed as well. The fact that smoke resulting from the explosion was seen spreading northeastward, southeastward, and southwestward was due to a marked shift in wind direction with height, as seen in the nearby Beijing rawinsonde report.

The explosion exhibted a signal in other Himawari-8 AHI bands as well. Band 5, at 1.6 µm and Band 6, at 2.3 µm are shown below (animations courtesy of William Straka, CIMSS); Similar animations are available for 3.9 µm, 6.2 µm (very faintly visible in this upper tropospheric water vapor channel), 7.0 µm, 7.3 µm and 8.6 µm and 10.35 µm.

A view of Himawari-8 shortwave IR imagery using the SSEC RealEarth web map server is shown below. In addition, an animation of Himawari-8 true-color images showing the dark smoke plume can be seen here.

========================== Added 14 August 2015 ===================

Suomi NPP VIIRS Day/Night Band (0.70 um) visible images on 9 August (before explosion) and 13 August (after explosion) [click to enlarge]

The Suomi NPP satellite overflew Tianjin before and after the explosion; VIIRS Day/Night Band images afford views that suggest power outages around the explosion site.

View only this post Read Less

1-minute interval GOES-14 SRSO-R visible (0.63 µm) images (above; click image to play animation) revealed the pulsing nature of the large Cougar Creek wildfire complex burning in southern Washington (not far southwest of Yakima) on 12 August 2015. The MP4 movie file is also available as a very large (128 Mbyte) animated GIF. The second fire blow-up that began around 1700 UTC apparently produced a pyrocumulonimbus cloud, with cloud-top IR Brightness Temperature (BT) values cooling past -40º C. Large amounts of smoke were transported northward and then northeastward away from the fire source region.

During the preceding overnight hours, a comparison of  1003 UTC Suomi  NPP VIIRS shortwave Infrared (3.74 µm), Day/Night Band (0.8 µm), and Infrared (11.45 µm) images (below) showed a very large shortwave IR fire “hot spot” (yellow to red to black pixels), with the large fire glowing very brightly on the Day/Night Band image; the coldest IR BT value of the cloud streaming northward from the fire was -53º C.

View only this post Read Less