2012年亚马逊森林火灾不会很严重

Forests in the Amazon Basin are expected to be less vulnerable to wildfires this year, according to the first forecast from a new fire severity model developed by university and NASA researchers. Fire season across most of the Amazon rain forest typically begins in May, peaks in September and ends in January. The new model, which forecasts the fire season's severity from three to nine months in advance, calls for an average or below-average fire season this year within 10 regions spanning three countries: Bolivia, Brazil and Peru.

"Tests of the model suggested that predictions should be possible before fire activity begins in earnest," said Doug Morton, a co-investigator on the project at NASA's Goddard Space Flight Center in Greenbelt, Md. "This is the first year to stand behind the model and make an experimental forecast, taking a step from the scientific arena to share this information with forest managers, policy makers, and the public alike."

The model was first described last year in the journal Science. Comparing nine years of fire data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite, with a record of sea surface temperatures from NOAA, scientists established a connection between sea surface temperatures in the Pacific and Atlantic oceans and fire activity in South America.

"There will be fires in the Amazon Basin, but our model predictions suggest that they won't be as likely in 2012 as in some previous years," said Jim Randerson of the University of California, Irvine, and principal investigator on the research project.

Specifically, sea surface temperatures in the Central Pacific and North Atlantic are currently cooler than normal. Cool sea surface temperatures change patterns of atmospheric circulation and increase rainfall across the southern Amazon in the months leading up to the fire season.

"We believe the precipitation pattern during the end of the wet season is very important because this is when soils are replenished with water," said Yang Chen of UC Irvine. "If sea surface temperatures are higher, there is reduced precipitation across most of the region, leaving soils with less water to start the dry season."