NASA's MODerate-resolution Imaging Spectroradiometer (MODIS) aboard the Terra and Aqua satellites has again been used to check our environment. This time, NASA satellites have been tracking the growth and the 'productivity' of U.S. forests. Even if satellite data doesn't permit to predict how future climate change will affect forests, the U.S. and Canadian researchers who used it found very interesting results. They also think that NASA's tools give them enough information to better understand the evolution of the forests and to react to sudden climate changes. But read more...
Here are some results obtained by studying data gathered by NASA's satellites.
Scientists have found that satellite measurements of tree species and growth in forested regions across the United States were often equivalent to those taken directly on the ground. The study relied on a sophisticated data product from NASA's MODerate-resolution Imaging Spectroradiometer (MODIS) aboard the Terra and Aqua satellites called the "enhanced vegetation index," a measure of forest productivity that can also be used to gauge the total number of tree species in a region.
Below you can see a picture of the "global tree cover as measured by the NASA's MODIS instrument aboard NASA's Terra and Aqua satellites, showing areas with little or no tree cover (white shades) to considerable tree cover (green shades)." (Credit: NASA/University of Maryland)
The MODIS data also shows that the overall productivity or growth of a forest in response to weather and seasonal conditions was closely linked to the number of different tree species it contains, allowing scientists to more readily infer the effects of climate change.
Here is a "false-color image of global primary productivity, as measured by MODIS. Blue-shaded areas show where plants absorbed as much as 60 grams of carbon per square meter. Areas shaded green and yellow indicate 40 to 20 grams of carbon absorbed per square meter. Red pixels show absorption of less than 10 grams of carbon per square meter and white pixels show little or no absorption. (Credit: NASA/GSFC)
[Note: you can access to larger versions of these illustrations on this page on NASA's web site.]
Here are some quotes from Richard Waring, professor emeritus of forest science at Oregon State University, who retired from the College of Forestry in January 2001 but still is very active.
"In anticipation of shifts in climate, accurate measurements of forest growth and composition are becoming more important," Waring said. "These new data help us better predict how forests may change so officials can implement environmental plans or regulations to lessen the impact in advance."
The NASA news release mentions that this research work has been published by Remote Sensing of Environment, an Elsevier scientific journal, but doesn't give any details. In fact, this paper has been published under the name "MODIS enhanced vegetation index predicts tree species richness across forested ecoregions in the contiguous U.S.A." (Volume 103, Issue 2, Pages 218-226, July 30, 2006). Here is a link to the abstract.
For more information, this journal has also published an article on a closely related subject in its latest issue, "Monitoring spring canopy phenology of a deciduous broadleaf forest using MODIS" (Volume 104, Issue 1, Pages 88-95, 15 September 2006). Here are two links to the abstract and to the full paper (PDF format, 8 pages, 557 KB).
Finally, after a close look at my archives, I realized that I've already mentioned NASA's MODIS several times. Please take a look to these previous posts.
- NASA Satellite Measures Earth’s Carbon Metabolism (April 25, 2003)
- NASA's Satellites Watch World's Cities Grow (December 13, 2003)
- Should Farmers Come Back to Towns? (July 30, 2004)
- Satellites Show Urban Effects on Climate (July 22, 2005)
Sources: NASA/Goddard Space Flight Center news release, via EurekAlert!, August 29, 2006; and various web sites
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