Variations in Suomi/NPP Day/Night Band Lunar Illumination
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