JPL Scientists Detect Early Signs of Flash Droughts, Offering Potential for Mitigation

In a recent study, a team led by Nicholas Parazoo, an Earth scientist at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, was able to detect signs of flash droughts up to three months before onset, potentially aiding future mitigation efforts.

Flash droughts, which can develop rapidly within weeks and are difficult to predict, have caused widespread crop failure and economic losses in the United States. The 2012 flash drought, in particular, led to losses costing more than $30 billion.

The JPL researchers compared years of plant fluorescence data from NASA’s Orbiting Carbon Observatory-2 (OCO-2) satellite, launched in 2014, to an inventory of flash droughts that struck the U.S. between May and July from 2015 to 2020. They found that in the weeks and months leading up to a flash drought, vegetation initially thrived as conditions turned warm and dry, emitting an unusually strong fluorescence signal.

“Plant fluorescence shows promise as a reliable early warning indicator of flash drought with enough lead time to take action,” said Parazoo, lead author of the study.

The team correlated the fluorescence measurements with moisture data from NASA’s Soil Moisture Active Passive (SMAP) satellite, also managed by JPL. A consistent pattern emerged across diverse U.S. landscapes, from temperate forests to the Great Plains and Western shrublands.

In addition to predicting flash droughts, the JPL scientists used OCO-2 carbon dioxide measurements and advanced computer models to track vegetation carbon uptake before and after these events. Surprisingly, they found that increased uptake prior to flash droughts fully offset decreases due to the ensuing hot conditions, potentially improving carbon cycle model predictions.

Both the OCO-2 project, celebrating its 10th year in orbit this summer, and SMAP are managed by JPL, which is located in Pasadena and operated by Caltech for NASA. The study’s findings could provide valuable early warning for local farmers and ranchers, allowing them to better manage water resources and crop planting in the face of impending flash droughts.