Washington: In July this year, farmers in the US Midwest and plains regions watched crops wilt and die after a stretch of unusually low precipitation and high temperatures.
Before a lack of rain and record-breaking heat signalled a problem, however, scientists observed another indication of drought in data from NASA and NOAA satellites: plant stress.
Scientists with the US Department of Agriculture`s Agricultural Research Service (USDA-ARS) have developed a way to use satellite data to map that plant stress, according to a USDA statement.
The maps could soon aid in drought forecasts, and prove useful for applications such as crop yield estimates or decisions about crop loss compensation.
"Crop drought monitoring is of high practical value, and any advance notice of drought conditions helps the farmer make practical decisions sooner," said Steve Running, ecologist at University of Montana.
Drought in 2012 was the most severe and extensive in at least 25 years, according to the USDA`s Economic Research Service.
By August, 60 percent of farms were in areas experiencing drought, and by mid-September USDA had designated more than 2,000 counties as disaster areas.
Martha Anderson with USDA-ARS said: "This year was record-breaking, this was just a huge event." She is working with a team to develop the plant stress indicator for drought.
These findings were presented at the American Geophysical Union meeting in San Francisco.
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