On September 27, 2012, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured this nighttime view of low-lying marine layer clouds along the coast of California.
The image was captured by the VIIRS “day-night band,” which detects
light in a range of wavelengths from green to near-infrared and uses
filtering techniques to observe signals such as gas flares, auroras,
wildfires, city lights, and reflected moonlight.
An irregularly-shaped patch of high clouds hovered off the coast of
California, and moonlight caused the high clouds to cast distinct
shadows on the marine layer clouds below. VIIRS acquired the image when
the Moon was in its waxing gibbous phase, meaning it was more than
half-lit, but less than full.
Low clouds pose serious hazards for air and ship traffic, but
satellites have had difficulty detecting them in the past. To illustrate
this, the second image shows the same scene in thermal infrared, the
band that meteorologists generally use to monitor clouds at night. Only
high clouds are visible; the low clouds do not show up at all because
they are roughly the same temperature as the ground.
Learn more about the VIIRS day-night band and nighttime imaging of Earth in our new feature story: Out of the Blue and Into the Black.
Instrument: Suomi NPP - VIIRS
