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Fall Color from Outer Space

Fall color came on strong earlier this month, and NASA's Earth-observing Terra and

Fall color came on strong earlier this month, and NASA's Earth-observing  Terra and Aqua satellites captured it from 438 miles (705 km) up. These photos were taken last Sunday and Monday, October 11-12 over the Great Lakes and eastern United States and Canada. I thought the Minnesota region blazed with orange and red until seeing northern Wisconsin and Michigan in this image. Wow!

Fall Color 2015 NASA Anno
Wider view showing several of the Great Lakes, Wisconsin, Michigan and part of Ontario. Click for a giant version. Credit: NASA images by Jeff Schmaltz, LANCE/EOSDIS Rapid Response

I searched for a photo taken a week later to compare but alas couldn't find one. Much of the fall color has faded for us; I'm guessing Michigan looks browner now as well.

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Fall leaf color bKing_S
With chlorophyll out of the way, carotenes and anthrocyanins come to the fore in this northern red oak leaf. Oddly enough, chlorophyll is an unstable molecule that has to be continually regenerated by the plant. With the necessary sunlight and warmth, it breaks down. Credit: Bob King

Fall color generally peaks around mid-October with falling temperatures and decreased sunshine, causing the breakdown of the green chlorophyll pigment in leaf cells. With the green gone, other pigments reveal themselves  such as carotene, responsible for the yellows we see, and the anthrocyanins that create the spectacular reds.

Peak color dates varies depending on your latitude — the further north you live, the shorter the daylight hours and the colder the temperatures — both factors that tell the trees winter's on its way. Striking fall colors were already obvious in chilly eastern Siberia as early as September 9 .  Max color sometimes doesn't reach the south until in mid-November. Elevation matters too, with fall color generally starting sooner at colder, higher altitudes.

As we're all aware, some years show more spectacular colors than others. According to NASA's Earth Observatory site , the weather before and during the transition plays a large role in color intensity. Brightest colors occur when dry, sunny days are followed by cool, dry nights.

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I hope you had clear skies earlier this morning to see the fine pairing of Mars and Jupiter with Venus on the sidelines. I was surprised by a dim but wildly-flaming aurora that blew up across the northern sky nearly to the zenith. It shot about so fast it looked explosive. The NOAA forecast calls for a minor G1 storm tonight, so be on the lookout.

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