NASA Satellite Takes Pictures Of Australian Wildfires
Why are NASA satellite images of the Western Australia so lit up? Scientists have confirmed that these images show wildfires taking place.
AsianScientist (Dec. 10, 2012) – Observers of NASA’s new “Black Marble” images of Earth at night released this week have noticed bright areas in the western part of Australia that are largely uninhabited. Why is this area so lit up, many have asked?
Away from the cities or industrial sites, scientists have confirmed that much of the night light observed by the NASA-NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) satellite in these images comes from wildfires.
The extent of the night lights in this area is also a function of composite imaging. These new images were assembled from data acquired over nine days in April 2012 and 13 days in October 2012.
Hence, fires and other lighting (such as ships) could have been detected on any one day and integrated into the composite picture to give the impression of a massive blaze, despite being temporary phenomena.
Other features appearing in uninhabited areas in these images could include fishing boats, gas flaring, lightning, oil drilling, or mining operations, which can show up as points of light. One example is natural gas drilling in the Bakken Formation in North Dakota.
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.
The nighttime view was made possible by the new satellite’s “day-night band” of the Visible Infrared Imaging Radiometer Suite. VIIRS 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. In this case, auroras, fires, and other stray light have been removed to emphasize the city lights.
In total, it took 312 orbits and 2.5 terabytes of data to get a clear shot of every parcel of Earth’s land surface and islands. The new data was then mapped over existing Blue Marble imagery of Earth to provide a realistic view of the planet.
“Night time imagery provides an intuitively graspable view of our planet,” says William Stefanov, a scientist in NASA’s International Space Station program office who has worked with similar images from astronauts.
“City lights are an excellent means to track urban and suburban growth, which feeds into planning for energy use and urban hazards, for studying urban heat islands, and for initializing climate models.”
Source: NASA; Photos: NASA Earth Observatory/NOAA NGDC.
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