Hmm. These are the same forests that we're, ummm, cutting down.
A team of scientists from the University of Colorado at Boulder and NASA's Jet Propulsion Laboratory in Pasadena, Calif., used the Tropospheric Emission Spectrometer on NASA's Aura satellite to gather data on "heavy" and "light" water vapor in order to retrace the history of water over oceans and continents, from ice and liquid to vapor and back again. The researchers were able to distinguish between the two because heavy water vapor molecules have more neutrons than lighter ones do.
By analyzing the distribution of the heavy and light molecules, the team was able to deduce the sources and processes that cycle water, the most abundant greenhouse gas in Earth's atmosphere, said David Noone of CU-Boulder's Cooperative Institute for Research in Environmental Sciences. Noone, an assistant professor in CU-Boulder's atmospheric and oceanic sciences department, is the corresponding author of a paper on the subject that appears in the Feb. 1 issue of Nature.
The team found that tropical rainfall evaporation and water "exhaled" by forests are key sources of moisture to the tropical atmosphere. The researchers noted that much more water than expected is transported into the lower troposphere over land than over oceans, especially over the Amazon River basin and in tropical Africa.
"One might expect most of the water to come directly from the wet ocean," said Noone. "Instead, it appears that thunderstorm activity over the tropical continents plays a key role in keeping the troposphere hydrated."
http://www.sciencedaily.com/releases/2007/02/070201093640.htm
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