Fall Colors from Space

Autumn Appears to Satellites as Green Becomes Orange

Sep 8, 2008 Kelly Whitt

Orbiting satellites detect the onset of fall as the green landscape far below shifts to autumn hues.

Satellites are constantly spying on Earth, uncovering human transformations of the land and natural disasters. But satellies also capture the natural progression of the seasons, as when a green, summer landscape turns to the orange tones of fall.

Fall Comes to the Great Lakes

NASA's Terra satellite is equipped with the Moderate Resolution Imaging Spectroradiometer, or MODIS for short. MODIS is able to image the changing autumn landscape from high above. While the date for the first day of fall occurs around September 22 every year, the date for the changing of the leaves varies depending on location climate factors. Yearly fluctuations in rainfall and temperature can affect the timing of the changing of the leaves and even how colorful the season will be.

The images here were taken in 2003 and 2007 around the Great Lakes region. The comparison in the image taken on October 6, 2003, and a mere four days later, on October 10, 2003, show the drastic change that can happen over a short period time. It also illustrates how difficult it can be to simply plan a vacation around the peak fall colors, as the peak time can quickly appear and then fade.

The northern part of Wisconsin and the Upper Peninsula of Michigan are known for thick forests. Mixed hardwoods and conifers populate the forests. Maple, birch, basswood, and ash are some of the more common hardwoods. The October 6 image still shows almost an entirely green swath along Lake Superior with no hint as to the sudden onset of fall colors.

The October 10 image shows the Apostle Islands, shorelines, and inland forests covered in rust tones. About halfway south through Wisconsin the orangish colors turn back to the familiar greens and browns of summer.

A More Gradual Onset of Fall Colors

In the image encompassing the entire Great Lakes region, taken in 2007, patches of fall color show up while other regions are still all green. Areas a bit inland from Lake Superior in Wisconsin and the UP show the landscape turning orange, while the east coast of Lake Superior in Ontario shows a spreading orange bloom. A few other inland areas of Ontario are also turning color as the trees undergo their fall change.

The St. Mary's River divides Canada from the United States and Ontario from Michigan, linking the waterways of Lakes Superior and Huron. On this date, September 23, 2007, the first day of fall for that year, the fall colors have not quite made the jump south of the river yet into neighboring Michigan.

Comparing the September 2007 image with the October 2003 image of northern Wisconsin and the UP also once again illustrates how the exact dates for fall colors can vary from year to year depending on that year's climatological conditions.

The copyright of the article Fall Colors from Space in Meteorology & Climatology is owned by Kelly Whitt. Permission to republish Fall Colors from Space in print or online must be granted by the author in writing.

Near Lake Supeior Oct 6, 2003