NASA | The Evaporative Stress Index

Uploaded by NASAexplorer on 05.12.2012

The Evaporative Stress Index (ESI) provides objective, high-resolution information
about the evaporation of water from landsurface
Overall, 2010 showed higher than average evaporation.
It was a relatively wet year despite occasional pockets of drought.
But in July, as a high pressure system developed over the Atlantic,
the ESI started to pick up signs of plant stress in the South East.
Crops were using less water than they normally do.
Over the Fall, signs of drought worsened and had spread Northward across much of the Eastern
part of the U.S.
The devastating drought that affected Texas in 2011
started in the winter and was impacting farmers and ranchers across the state by April.
Wildfires were common that year and cattle had little to eat.
By the summer of 2011, the ESI shows extremely
dry conditions across all of Texas, Louisiana, and Oklahoma.
More than 10 billion dollars in agricultural losses
for the South were recorded that year.
The la Nina whether pattern which caused these dry conditions and the resulting economic losses
lasted through the end of 2011.
As early as May of this year, the ESI showed plant stress in the Corn Belt region.
The combination of a heat wave and precipitation deficits drove moisture
out of the soil. Corns and soybeans, a stable of the global
food supply, would be severely impacted later in the year.
The ESI picked up on warning indicators a month before The U.S. Drought Monitor.
The kind of early-warning detection system it provides
will enhance the US arsenal of drought monitoring tools and help
farmers adapt to drought before it evolves.