Earth at Night 2001This
is what the Earth looks like at night. Can
you find your favorite country or city? Surprisingly,
city lights make this task quite possible.
Human-made lights highlight particularly developed
or populated areas of the Earth's surface,
including the seaboards of Europe, the eastern
United States, and Japan. Many large cities
are located near rivers or oceans so that
they can exchange goods cheaply by boat. Particularly
dark areas include the central parts of South
America, Africa, Asia, and Australia. The
above image is actually a composite of hundreds
of pictures made by the Defense Meteorological
Satellite Program (DMSP) currently operates
four satellites carrying the Operational Linescan
System (OLS) in low-altitude polar orbits.
Three of these satellites record nighttime
data. The DMSP-OLS has a unique capability
to detect low levels of visible-near infrared
(VNIR) radiance at night. With the OLS "VIS" band
data it is possible to detect clouds illuminated
by moonlight, plus lights from cities, towns,
industrial sites, gas flares, and ephemeral
events such as fires and lightning-illuminated
clouds. The Nighttime Lights of the World
data set is compiled from the October 1994
- March 1995 DMSP nighttime data collected
when moonlight was low. Using the OLS thermal
infrared band, areas containing clouds were
removed and the remaining area used in the
time series. This animation is derived from
an image created by Craig Mayhew and Robert
Simmon from data provided by Christopher Elvidge
of the NOAA National Geophysical Data Center. |
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Earth's Nightlights |
08.15.03 |
United States at Night. Courtesy: DMSP and NASA. Click image to see larger picture. Unlike yesterday, the bustling U.S. East Coast is normally ablaze in nighttime light, with its cities growing closer and closer together. NASA researchers use these images of nighttime lights to study weather around urban areas. Weather stations were classified as urban, near-urban or rural depending on the brightness around them and their records adjusted to account for human influence. These images are actually a composite of hundreds of pictures made by U.S. Defense Meteorological Satellites Program (DMSP). The Nighttime Lights of the World is compiled from the October 1994 - March 1995 data, which was collected when moonlight was low.
For more information on how this image was created, visit the Scientific Visualization Studio. For more information on how NASA uses these images for research, visit the Satellites Shed Light on a Warmer World site. Rani Chohan NASA Goddard Space Flight Center |
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