BOSTON, March 29 (UPI) -- An analysis of satellite data reveals widespread damage to Amazon forests caused by last year's record drought, U.S. researchers say.

"The greenness levels of Amazonian vegetation -- a measure of its health -- decreased dramatically over an area more than 3 1/2 times the size of Texas and did not recover to normal levels, even after the drought ended in late October 2010," lead study author Liang Xu of Boston University said.


In a changing climate with warmer temperatures and altered rainfall patterns, moisture stress could cause some Amazon rainforests to be replaced by grasslands or woody savannas, while the release of carbon stored in the dead, rotting wood into the atmosphere could accelerate global warming, researchers say.

The study used more than a decade's worth of data from a NASA weather science satellite.

The analysis showed the 2010 drought reduced the greenness of about 965,000 square miles of vegetation in the Amazon -- more than four times the area affected by the last severe drought in 2005.

The severity of the 2010 drought also was seen in records of water levels in rivers across the Amazon basin.

"Last year was the driest year on record based on 109 years of Rio Negro water level data at the Manaus harbor," Marcos Costa, a co-author from the Federal University in Vicosa, Brazil, said.

"For comparison, the lowest level during the so-called, once-in-a-century drought in 2005 was only eighth lowest," he said.

The study has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union, an AGU release said Tuesday.