Agriculture is the economic engine that powers the Great Plains, the vast stretch of treeless prairie that covers parts of 10 states – and where the next drought can appear with little warning.
Now there’s a powerful new tool to help provide farmers and ranchers in the arid western United States critical early indications of oncoming droughts, and its name is EDDI.
EDDI, or the Evaporative Demand Drought Index, is the brainchild of Mike Hobbins, a CIRES scientist working at NOAA’s Boulder lab, to estimate the changing “thirst” of the atmosphere.
“Evaporative demand is the thirst of the atmosphere for any water: on the surface, in lakes and rivers, in the ground or in plants,” Hobbins said.
Surface moisture is really hard to measure because a major component is soil moisture, which varies dramatically over very short distances.
Evaporative demand is relatively easy to measure because it’s based on air temperature, humidity, wind speed, and solar radiation, which we measure all the time.” Proven in the field Over the past few years, EDDI has steadily demonstrated its potential, accurately signaling the development of a 2015 drought in Wyoming and 2016 droughts in South Dakota’s Black Hills and the southeastern United States.
For Mark Svoboda, co-founder of the U.S. Drought Monitor, that was what he needed to see.
“What’s unique about it is that it detects drought emergence at weekly time scales.
“When we got to June and July, things started to happen fast: crop conditions were tanking, we started seeing a lot of heat – EDDI was pretty much all over it at that point.” [This map of Evaporative Demand Drought Index values across the U.S. for the 30 days prior to June 1 shows the relative “thirst” of the atmosphere in the northern Great Plains as a severe drought began to take hold.]
The U.S Famine Early Warning System network, which helps governments and relief agencies plan for and respond to humanitarian crises, has also begun using EDDI to help provide early warning of food insecurity (limited access to sufficient food supply) around the world.