Signals from space help predict drought early

A recent study by NASA scientists can help detect flash drought signals up to 3 months before it occurs, contributing to future damage mitigation efforts.

Normal droughts can develop slowly seasonally, while flash droughts occur as a result of rapid drying.

NASA satellites can detect bright light from SIF - (Photo: NASA).

According to phys.org on May 14, in recent research, scientists at the Jet Propulsion Laboratory (JPL) of the US Aeronautics and Space Administration (NASA) were able to detect signals . early flashes of drought by tracking the "glow" from chlorophyll fluorescence (known as sunlight-induced fluorescence - SIF ).

Chlorophyll will emit light when exposed to sunlight during photosynthesis. The stronger the fluorescence, the more carbon dioxide the plant takes in from the air to grow.

Although invisible to the naked eye, this bright light can be detected by instruments on satellites such as NASA's Orbiting Carbon Observing-2 satellite.

The research team compared the fluorescence data with data on flash droughts in the US between May and July from 2015 to 2020.

They discovered a domino effect when they found that in the weeks and months before the flash drought, vegetation initially flourished as weather conditions turned warm and dry. The thriving plants emitted an unusually strong fluorescence signal for the said time of year.

When extreme temperatures strike, the already low soil moisture drops even more and flash drought occurs.

The research team correlated the fluorescence data with humidity data from NASA satellites. They found that abnormal fluorescence levels were strongly associated with loss of soil moisture in the six to 12 weeks before a flash drought.

They tested this association in different terrains, from the forests of the Eastern United States to the great plains and shrublands of the west, with consistent results.

A field is preparing for the growing season in Kentucky, USA - (Photo: US Department of Agriculture).

For this reason, SIF "promises to be a reliable early warning signal of flash drought with enough time to act ," said scientist Nicholas Parazoo, lead author of the study.

Although early warning cannot eliminate the impact of flash droughts , it can help farmers and ranchers proactively increase irrigation water to reduce the impact on crops.

Breaking out quickly and without much warning, a flash drought hit much of the United States in 2012 as extremely high temperatures sapped moisture from soil and crops, causing widespread crop failures and further economic losses. 30 billion USD.