May 14th, 2013
GOES-13 0.63 µm visible channel (top) and 3.9 µm shortwave IR channel (bottom) images (click to play animation)
McIDAS images of GOES-13 0.63 µm visible channel and 3.9 µm shortwave IR channel data (above; click image to play animation) showed the large smoke plumes and fire “hot spots” (dark black pixels on the shortwave IR imagery) associated with the Germann Road Fire in northwestern Wisconsin and the Green Valley Fire in Minnesota on 14 May 2013. The Germann Road Fire burned 8495 acres, making it the largest wildfire in northern Wisconsin in 33 years. In Minnesota, the Green Valley fire burned 7100 acres.
Items of interest to note on the GOES-13 imagery: (1) the presence of a well-defined lake breeze (lighter gray color enhancement on the IR images) which extended quite a distance inland from the colder waters of Lake Superior (which still exhibited Sea Surface Temperature values in the middle to upper 30s F); (2) the change in wind direction from southwesterly to westerly/northwesterly as a frontal boundary moved eastward across the region; (3) the apparent “flare-up” of the Germann Road Fire as the frontal boundary arrived around 00:45 UTC — the size of the cluster of black “hot spot” pixels increased on the shortwave IR image, concurrent with the rapid growth of an area of pyrocumulus clouds; (4) the eastward motion of the thin lake ice that remained on Mille Lacs in Minnesota (the large lake just south of the Green Valley smoke plume).
2 days after the fire, the burn scar was apparent on an Aqua MODIS false-color Red/Green/Blue (RGB) image (below), viewed using the SSEC Web Map Server. Note the “right turn”on the northern end of the burn scar, caused by a change from southwesterly winds to strong westerly winds in the wake of a frontal passage (which altered the direction of the fire’s progress).
Aqua MODIS false-color image showing wildfire location and burn scar
January 22nd, 2013
Suomi/NPP VIIRS Day/Night Band Imagery (click image to toggle between times)
The Day/Night band on Suomi/NPP produces Night-Time visible imagery using illumination from natural (the moon, forest fires) and man-made sources (city lights, gas flares). Interpretation of the imagery should be done, therefore, with a knowledge of the Lunar phase. In the example above, note the dimming of the clouds over the central plains of the United States between 0752 UTC and 0933 UTC. The 0933 UTC image also shows a gradation in the cloud brightness from east to west — clouds off the west coast of the United States are brighter than clouds over the Plains. The waxing gibbous moon is more than 80% full on 22 January, providing ample light when above the horizon. Moonset occurred over the central USA around 0900 UTC on 22 January; on the West Coast, moonset was closer to 1100 UTC. In the later image, only the regions west of the Rockies are illuminated by the Moon; elsewhere the moon has set, and this is reponsible for the differences in how the clouds are presented.
The 0752 UTC image also contains an excellent example of Moon Glint over the southern Gulf of California. The setting moon is low in the sky, and reflection off the ocean surface is detected.
These images can also be observed using the SSEC Web Map Server. The image below that includes Day/Night Band imagery and Suomi/NPP Tracks was produced with this url.
Suomi/NPP VIIRS Day/Night Band Imagery produced by SSEC WMS
December 5th, 2012
Suomi NPP VIIRS Day/Night Band composite (global view)
On 05 December 2012 NASA and the NOAA National Geophysical Data Center (NGDC) jointly released a “Black Marble” global composite of night-time Suomi NPP VIIRS 0.7 µm Day/Night Band imagery (collected from multiple cloud-free satellite overpasses in April and October 2012) — the image above shows this dataset visualized using the SSEC Web Map Server. See the NASA news story and the SSEC news story for additional details.
Suomi NPP VIIRS 0.7 µm Day/Night Band composite image (North America)
A closer view of North America is shown above, with a zoomed-in image centered on Madison, Wisconsin shown below.
Suomi NPP VIIRS 0.7 µm Day/Night Band composite image (centered on Madison, WI)
Many examples of the VIIRS Day/Night Band showing a variety of phenomena can be found elsewhere on the CIMSS Satellite Blog.
September 25th, 2012
Suomi NPP VIIRS 0.7 µm Day/Night Band image + 11.45 µm IR channel image
AWIPS images of Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR channel data (above) showed a thunderstorm complex that stretched from northern Missouri to southern Illinois at 08:23 UTC (3:23 AM local time) on 25 September 2012. The IR image revealed a number of cold overshooting tops (exhibiting IR brightness temperatures as cold as -79 C), while the Day/Night Band image showed several bright “streaks” which were signatures of lightning illuminating the cloud tops as the VIIRS instrument was scanning the feature. Note how many city lights were able to be seen through the veil of thin cirrus around the edges of the thunderstorms.
The SSEC Web Map Server offered a larger scale view (below), also combining the Suomi NPP VIIRS Day/Night Band and IR images with the legacy IR difference “fog/stratus product”.
Suomi NPP 0.7 µm Day/Night Band + 11.45 µm IR channel + IR difference “fog/stratus product”