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Mercredi, 07 Décembre 2011 23:17

City Lights Seen From Space Reveal How Countries Change

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You can tell a lot about a country from its lights.

New research suggests that NASA’s Defense Meteorological Satellite Program Operational Linescan System — a series of satellites that have been taking pictures of nighttime lights on Earth’s surface for nearly 20 years — can reveal details about changes happening on the ground.

“We can now ask how does observed lighting behave in response to things such as population and economic growth, external investments, war, and economic collapse,” said Christopher Elvidge, who leads the National Geophysical Data Center’s Earth Observatory Group, during a presentation at the 2011 American Geophysical Union meeting on Dec. 7.

For instance, the satellites saw a steep decline in lighting in Rwanda in 1994 and the following years, reflecting that country’s civil conflict and genocide. Similarly, a civil war in Cote d’Ivoire from 2002 to 2004 severely darkened the country, with lights only returning in recent years. As well, increased lighting in Iraq in 1999 corresponded to the UN lifting import restrictions at the time, while external investment in Afghanistan led to increases in satellite-observed lighting starting in 2002.

Perhaps not surprisingly, countries undergoing rapid growth, such as China, had a high correlation between lighting and both GDP and population. In contrast, highly developed countries, such as the U.S. and Western Europe, showed fairly stable lighting patterns that didn’t shift despite increases in population and GDP.

The researchers also observed that countries showing little relationship between lighting and either population or GDP — including those in Eastern Europe and Africa — often had some sort of internal instability, which often affected their electric power systems.

Below you can see a video showing India’s lighting changes over the last 20 years.



City Lights Seen From Space Reveal How Countries ChangeAdam is a Wired Science reporter and freelance journalist. He lives in Oakland, Ca near a lake and enjoys space, physics, and other sciency things.
Follow @adamspacemann on Twitter.


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