Home > News > NASA-NOAA Satellite Reveals Stunning Views of Earth at Night
NASA-NOAA Satellite Reveals Stunning Views of Earth at Night Posted by Guy Pirro on 12/12/2012 8:32 PM
This image of the United States at night is a composite assembled from data acquired by the Suomi NPP satellite in April and October 2012. The image was made possible by the new satellite's "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. Named for satellite meteorology pioneer Verner Suomi, NPP flies over any given point on Earth's surface twice each day. 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. (Image Credit: NASA Earth Observatory image by Robert Simmon using Suomi NPP VIIRS data provided courtesy of Chris Elvidge - NOAA National Geophysical Data Center)
Scientists unveiled an unprecedented new look at our planet at night. A global composite image, constructed using cloud-free night images from a new NASA and National Oceanic and Atmospheric Administration (NOAA) satellite, shows the glow of natural and human-built phenomena across the planet in greater detail than ever before.
Many satellites are equipped to look at Earth during the day, when they can observe our planet fully illuminated by the sun. With a new sensor aboard the NASA-NOAA Suomi National Polar-orbiting Partnership (NPP) satellite launched last year, scientists now can observe Earth's atmosphere and surface during nighttime hours.
Earth at Night
This view of Earth at night is a cloud-free view from space as acquired by the Suomi National Polar-orbiting Partnership Satellite. A joint program by NASA and NOAA, Suomi NPP captured this nighttime image by the day-night band of the satellite's Visible Infrared Imaging Radiometer Suite VIIRS. It combines the Earth at night view created by NASA's Earth Observatory with data processed by NOAA's National Geophysical Data Center with the EO Blue Marble: Next Generation. (Credit: NASA Goddard, NASA's Earth Observatory, NOAA, DOD)
The new sensor, the day-night band of the Visible Infrared Imaging Radiometer Suite (VIIRS), is sensitive enough to detect the nocturnal glow produced by Earth's atmosphere and the light from a single ship in the sea. Satellites in the U.S. Defense Meteorological Satellite Program have been making observations with low-light sensors for 40 years. But the VIIRS day-night band can better detect and resolve Earth's night lights.
The new, higher resolution composite image of Earth at night and other VIIRS day-night band images are providing researchers with valuable data for a wide variety of previously unseen or poorly seen events.
"For all the reasons that we need to see Earth during the day, we also need to see Earth at night," said Steve Miller, a researcher at NOAA's Colorado State University Cooperative Institute for Research in the Atmosphere. "Unlike humans, the Earth never sleeps."
The Black Marble
This new global view and animation of Earth's city lights is a composite assembled from data acquired by the Suomi NPP satellite. The data was acquired over nine days in April 2012 and 13 days in October 2012. It took 312 orbits to get a clear shot of every parcel of Earth's land surface and islands. This new data was then mapped over existing Blue Marble imagery of Earth to provide a realistic view of the planet. (Credit: NASA Earth Observatory, NOAA NGDC)
"NOAA's National Weather Service is continuing to explore the use of the day-night band," said Mitch Goldberg, program scientist for NOAA's Joint Polar Satellite System. "The very high resolution from VIIRS data will take forecasting weather events at night to a much higher level."
Unlike a camera that captures a picture in one exposure, the day-night band produces an image by repeatedly scanning a scene and resolving it as millions of individual pixels. Then, the day-night band reviews the amount of light in each pixel. If it is very bright, a low-gain mode prevents the pixel from oversaturating. If the pixel is very dark, the signal is amplified.
"It's like having three simultaneous low-light cameras operating at once and we pick the best of various cameras, depending on where we're looking in the scene," Miller said. The instrument can capture images on nights with or without moonlight, producing crisp views of Earth's atmosphere, land, and ocean surfaces.
"The night is nowhere as dark as we might think," Miller said. And with the VIIRS day-night band helping scientists to tease out information from human and natural sources of nighttime light, "we don't have to be in the dark anymore, either."
"The remarkable day-night band images from Suomi NPP have impressed the scientific community and exceeded our pre-launch expectations," said James Gleason, Suomi NPP project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.
"Nighttime light is the most interesting data that I've had a chance to work with." says Chris Elvidge, who leads the Earth Observation Group at NOAA's National Geophysical Data Center. "I'm always amazed at what city light images show us about human activity." His research group has been approached by scientists seeking to model the distribution of carbon dioxide emissions from fossil fuels and to monitor the activity of commercial fishing fleets. Biologists have examined how urban growth has fragmented animal habitat. Elvidge even learned once of a study of dictatorships in various parts of the world and how nighttime lights had a tendency to expand in the dictator's hometown or province.