This image of part of the Atlantic coast of South America was acquired by the Suomi NPP satellite on the night of July 20, 2012. The image was made possible by the “day-night band” of the Visible Infrared Imaging Radiometer Suite (VIIRS), which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe dim signals such as city lights, gas flares, auroras, wildfires, and reflected moonlight.
“Nothing tells us more about the spread of humans across the Earth than city lights,” says Chris Elvidge, who leads the Earth Observation Group at NOAA’s National Geophysical Data Center. Away from the cities, some of the lights in the image may be wildfires (inland) or fishing boats (offshore).
Named for satellite meteorology pioneer Verner Suomi, NPP flies over any given point on Earth's surface twice each day at roughly 1:30 a.m. and p.m. The polar-orbiting satellite flies 824 kilometers (512 miles) above the surface, sending its data once per orbit to a ground station in Svalbard, Norway, and continuously to local direct broadcast users distributed around the world. Suomi NPP is managed by NASA with operational support from NOAA and its Joint Polar Satellite System, which manages the satellite's ground system.
To 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. To view the video of Earth’ night lights, visit our YouTube page. To view many more still images and maps of night lights, visit our new gallery page: Earth at Night 2012.