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Video at link: http://www.adventure-journal.com/201...arth-at-night/
6646x3340 version here, and damn it's cool: http://www.nasa.gov/images/content/7...635d38a1_o.jpg
6646x3340 version here, and damn it's cool: http://www.nasa.gov/images/content/7...635d38a1_o.jpg
Using a new sensor aboard a joint NASA-NOAA satellite, scientists now can observe Earth’s atmosphere and surface during nighttime hours, and the sensor is able to capture exceedingly low light — like the glow from a single ship at sea. The latest data was used to make a composite film of the entire planet at night. Unlike a camera that captures a picture in one exposure, the day-night band detector on the sensor 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 pixel by pixel.
With its night view, the satellite is able to detect a more complete view of storms and other weather conditions, such as fog. Or, as in the case of the composite image, no weather at all, since this is a combination created above clear skies all over the world and then stitched together into a cohesive whole. Sick, huh?
With its night view, the satellite is able to detect a more complete view of storms and other weather conditions, such as fog. Or, as in the case of the composite image, no weather at all, since this is a combination created above clear skies all over the world and then stitched together into a cohesive whole. Sick, huh?
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.
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. The sensor, called "VIIRS" (short for Visible Infrared Imaging Radiometer Suite), is sensitive enough to detect the light from a single ship in the sea.
The day-night band of VIIRS observed Hurricane Sandy, illuminated by moonlight, making landfall over New Jersey on the evening of Oct. 29. Night images showed the widespread power outages that left millions in darkness in the wake of the storm. With its night view, VIIRS is able to detect a more complete view of storms and other weather conditions, such as fog, that are difficult to discern with infrared, or thermal, sensors. Night is also when many types of clouds begin to form.
"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 day-night band of VIIRS observed Hurricane Sandy, illuminated by moonlight, making landfall over New Jersey on the evening of Oct. 29. Night images showed the widespread power outages that left millions in darkness in the wake of the storm. With its night view, VIIRS is able to detect a more complete view of storms and other weather conditions, such as fog, that are difficult to discern with infrared, or thermal, sensors. Night is also when many types of clouds begin to form.
"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."
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