UNIVERSITY OF TEXAS IN AUSTIN
Just like flash floods, droughts happen quickly – drying out the soil rapidly in a matter of days to weeks. These events can wipe out crops and cause huge economic losses. And according to scientists, the rate at which they dry out the landscape is increasing.
Researchers at the University of Texas at Austin, Hong Kong Polytechnic University and Texas Tech University have found that although the number of flash droughts has remained stable over the past two decades, many droughts occur faster. Globally, the fastest-growing flash droughts – leaving areas dry within just five days – have increased by about 3%-19%. And in places that are particularly prone to flash droughts – such as South Asia, Southeast Asia and Central North America – that increase is around 22%-59%.
Co-author and UT Jackson Professor, Zong-Liang Yang, said rising global temperatures are probably responsible for the faster onset, said co-author and UT Jackson School of Science professor Zong-Liang Yang, who added that the study’s results underscore the importance of understanding flash droughts and preparing for their effects.
“Every year, we’re seeing record-breaking warming, and that’s a good premise for these flash droughts,” he said. “Hope and Purpose” [of this research] is to minimize adverse effects”.
Research published in Nature Communications. The research was led by doctoral student Yamin Qing and Professor Shuo Wang, both of Hong Kong Polytechnic University.
Flash droughts are relatively new to science, with the advancement of remote sensing technology over the past few decades helping to reveal instances of rapidly drying out soils. This is seen as an indication of the beginning of a flash drought and can make the drought situation seem unusual.
As the name suggests, flash droughts are short-lived, usually lasting only a few weeks or months. But when they occur during a critical growth period, they can cause disaster. For example, in the summer of 2012, a flash drought in the central United States caused the corn crop to wither, resulting in an estimated $35.7 billion in damage.
In this study, scientists analyzed global hydro-climate datasets that use satellite soil moisture measurements to capture a global picture of flash drought and how it has changed. like over the past 21 years. The data shows that about 34%-46% of flash droughts occur in about 5 days. The rest appeared within a month, with more than 70% developing in a fortnight or less.
When they looked at droughts over time, they found that flash droughts happened more quickly.
The study also shows the importance of humidity and changing weather patterns, with the potential for faster droughts as there is a transition from wet to arid conditions. That leaves areas with seasonally variable humidity — such as Southeast Asia, the Amazon Basin, the East Coast and the Gulf Coast of the United States — into rapid drought hotspots.
“We should pay attention to vulnerable areas with a high probability of simultaneous soil drought and atmospheric aridity,” said Wang.
Mark Svoboda, director of the National Center for Drought Mitigation and originator of the term “flash drought,” says advances in drought detection technology and modeling tools — such as tools used in this study – has led to increased awareness of the effects and impacts of flash drought. The next important step, he said, is to translate this knowledge into actual planning.
“You can go back and see how the drought was going in 2012 and then compare it with that tool,” said Svoboda, who was not involved in the study. “We’ve really been well prepared to do a better job of monitoring these droughts.”
The research was funded by the National Natural Science Foundation of China and the Hong Kong Research Funding Council.
DOI
ARTICLE TITLE
Accelerate flash droughts caused by the combined effects of soil moisture loss and atmospheric aridity
ARTICLE PUBLICATION DATE
April 3, 2022
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