This new space-based view of Earth’s city lights is a composite assembled from data acquired by the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite. The data was acquired over nine days in April 2012 and thirteen days in October 2012. It took the satellite 312 orbits and 2.5 terabytes of data to get a clear shot of every parcel of Earth’s land surface and islands. This new data was then mapped over existing MODIS Blue Marble imagery to provide a realistic view of the planet.
The view was made possible by the “day-night band” of Suomi NPP’s Visible Infrared Imaging Radiometer Suite. VIIRS detects light in a range of wavelengths from green to near-infrared and uses “smart” light sensors to observe dim signals such as city lights, auroras, wildfires, and reflected moonlight. This low-light sensor can distinguish night lights tens to hundreds of times better than previous satellites. https://svs.gsfc.nasa.gov/30082