The Black Marble

[ChrisMC]

Cool picture of the Earth at night. The difference between East and West U.S. is nuts.

NASA is known for its "Blue Marble" images, which show Earth's sunlit disk as seen from space — and now it's making a splash with the nighttime view, nicknamed the "Black Marble."

This picture of the night lights of North and South America is just one frame in the Black Marble series, which is based on data from the Suomi NPP satellite and was unveiled today during the American Geophysical Union's fall meeting in San Francisco. The image has been built up from readings made by the weather/climate satellite's Visible Infrared Imaging Radiometer Suite, or VIIRS.

It'd be tough to snap this kind of picture at any single moment, because of cloud cover as well as seasonal changes in the way sunlight falls on our planet. Suomi NPP's handlers had an easier job, because the satellite could make multiple passes in April and October. Those fly-overs produced data that could be presented as a full-disk nighttime view of Earth.

NASA says the VIIRS instrument's "day-night band" is well-suited to pick up on dim signals such as city lights as well as gas flares, auroras, wildifires and reflected moonlight. For the Black Marble images, stray sources of light were removed during processing to emphasize the city lights.
"Artificial lighting is an excellent remote-sensing observable and proxy for human activity," Chris Elvidge, who leads the Earth Observation Group at the National Oceanic and Atmospheric Administration's National Geophysical Data Center, said in today's image advisory.

Weather forecasters are using the VIIRS imagery to track fog and low clouds through the night — which can be a concern for high-traffic coastal airports such as San Francisco. But it's not just about the weather: Researchers can track night lights over time to estimate economic activity and population growth. For example, satellite images graphically show how North Korea's economic development has lagged behind that of its neighbors, or how India has developed through the decades. Night-light pictures can also help facility planners decide where to put astronomical observatories that need dark skies, or help emergency officials gauge the extent of power outages.

"For all the reasons that we need to see Earth during the day, we also need to see Earth at night," Steve Miller, a researcher at NOAA's Colorado State University Cooperative Institute for Research in the Atmosphere, said in a NASA news release. "Unlike humans, the Earth never sleeps."

[Bromptonboy]

Be interesting see this same shot right after hurricane Sandy, and see the blacked out areas.