Researchers have stitched together a nighttime image of Berlin from above, which they say is the highest-resolution picture of a city at night. Ecologists have used the image to measure light pollution in the German capital.
The 878-megapixel picture, with one pixel per square meter, combines 2,647 aerial photographs taken from a research aircraft 1.8 miles (3 kilometers) above the city in September 2010, according to a statement from Freie Universität Berlin on Monday (Sept. 10). Researchers from the university and their collaborators at the Leibniz Institute of Freshwater Ecology and Inland Fisheries analyzed the image to measure the amount of upward-directed light and to find patterns in its distribution in the city across various land uses.
More than a third of the light came from Berlin's streets, illuminated by auto headlights, streetlights and advertisements, the researchers reported in the November 2012 issue of the journal Remote Sensing of Environment. The researchers also found light was spread unevenly throughout the city. Natural areas, such as Grunewald and Tempelhofer Park, made up almost a third of the study area, but emitted only 6 percent of the total light.
Light pollution has been found to have serious environmental impacts. Beyond sucking up energy, excessive lighting can confuse migrating birds and exposure to light at night has been linked to depression and other health consequences in humans.