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October 15, 2012 - Fall colors in the Mid-Atlantic
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10/11/2012 |
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As the hot, dry summer gave way to cooler autumn temperatures, the annual spectacle of bright fall colors was well underway in the Mid-Atlantic United States by early October, 2012. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite captured this true-color image of the shifting shades on October 11 at 18:30 UTC (2:35 p.m. EDT).
Autumn colors come first to northern latitudes and higher elevations. In New York State, which is partially visible at the very top of this image, and in Pennsylvania, colors are brightest, as well as along to tops of the ridge-and-valleys of the Appalachian Mountains, which can be seen traversing seven states in this image: New York, Pennsylvania, Maryland, West Virginia, Virginia, Tennessee and northern Georgia. The highlands of western North Carolina, although not as strikingly ridge-and-valley in nature, are also part of the Appalachian system. This area, along the border with Tennessee, is colored orange as the leaves begin to change.
The bright colors of autumn come from pigments found in leaves which are normally hidden by the green pigment, chlorophyll, which is needed in the warmer seasons to convert the sun’s energy into nourishment for the tree. When shorter days and cooler temperatures arrive, trees begin to move the nutrients to their roots, safe from winter frosts. As unneeded chlorophyll breaks down, the other pigments present in the leaf – anthocyanins (red and purple) and carotenoids (yellow, orange and brown)- can then show their colors.
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