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Early Fall Colors: Earth Image of the Week October 5, 2012
Upper MIchigan Fall Foliage from Space.
Temperatures were warming from near freezing at dawn to an afternoon high of 60 at Houghton when this midday image was captured by NASA's Aqua satellite.
The lengthening shadows of autumn and a few frosty nights have led to fall foliage colors arriving about a week early across the upper Mississippi Valley and western Great Lakes.

A protracted drought is also responsible for accelerating the annual chromatic shift, according to Michigan State horticulturists who told the Detroit Free Press the color season is likely to be early, brief and brilliant.

The true-color image to the right was captured by NASA’s Aqua satellite at 1:50 p.m. Central Daylight Time on September 30, 2012. The image was brightened to compensate for the dimmer illumination of autumn at such a high latitude.

It shows brilliant reds and burnt orange colors of Michigan’s Upper Peninsula and adjacent areas of Wisconsin and Minnesota.

Fall colors were nearly at their peak in Michigan’s Ottawa, Chequamegon and Hiawatha national forests on the Upper Peninsula.

Autumn’s rich tapestry is the result of chemical processes that take place in the tree as the season changes. During spring and summer, the leaves served as factories where most of the foods necessary for the trees' growth are manufactured.

This food-making process takes place in numerous cells containing the pigment chlorophyll, which gives the leaf its green color. Along with the green pigment, leaves contain yellow or orange carotenoids, which also give the carrot its familiar color.

Most of the year, these yellowish colors are masked by the greater amount of green coloring provided by the chlorophyll. But in the fall, partly because of changes in the period of daylight and changes in temperature, the leaves stop their food-making process.

The chlorophyll breaks down, the green color disappears and the yellowish colors that remain become visible and give the leaves part of their fall splendor. Other chemical changes occur, leading to the formation of additional pigments that vary from yellow to red to blue.

Image: CIMSS