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Tue December 18, 2012
Study: Midwest Drought Onset Faster Than First Thought
New research shows how quickly and dramatically plants in Wisconsin came under stress this year.
According to the US Department of Agriculture, the drought that has afflicted much of the United States this year has been the most severe in at least 25 years. But the federal agency wants to do more than simply report the bad news.
It’s come up with a way to track how plant life is faring by using satellites to monitor what is known as "evapotranspiration" – or ET for short. ET is the exchange of water vapor between the surface of the earth and the atmosphere and it’s critical to plant health.
Changes to ET in southern Wisconsin this year has been significant. Martha Anderson is one of the people immersed in the work. She’s a research physical scientist with USDA’s Agricultural Research Service.
"Usually, drought kind of creeps on us rather slowly," she says, "but this last year, everything went south really quite quickly."
Anderson tells WUWM Environmental Reporter Susan Bence her career wasn’t remotely heading in that direction until she was introduced to soil science at UW-Madison.
"I got my PhD actually in astrophysics, and I kind of realized 5, 6 years into my PhD program that I was much more interested in things that were going on on Earth, than I was on things that were going on out in the galaxy."
And so her attentions landed back on Earth, and she began studying how to measure and predict severe droughts. She recently co-edited a book entitled Remote Sensing of Drought: Innovative Monitoring Approaches.
She says her research has helped her to understand the multiple causes of droughts like this past year's.
"It was a compound cause for this drought," she says. "We had both below normal rainfall over much of the Central United States, but if you remember early last year, it was unseasonably warm. There's this lingering heat wave and it really drove some large evaporative fluxes. Essentially early in the season, it just baked the moisture right out of the soil."
Being able to track factors like rainfall deficits and high temperatures, Anderson says, could have a lot of potential effects.
"Having a index that can capture early in the process of (a)...draught signs of rapidly developing stress is going to help us stabilize the food market, people can make better adaptive management decisions in the United States. Globally, if we can identify areas of deteriorating conditions early on, that can help mobilize aid that can address yield losses and potential famine."
She says being able to prevent rapid onset droughts will be necessary as climate patterns become increasingly unstable and variable.