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’Flash droughts’ coming on faster, global study shows

Phys.org/news (APRIL 1, 2022)

Titre : ’Flash droughts’ coming on faster, global study shows

Just like flash floods, flash droughts come on fast—drying out soil in a matter of days to weeks. These events can wipe out crops and cause huge economic losses. And according to scientists, the speed at which they dry out the landscape has increased

Phys.org/news (APRIL 1, 2022)

Présentation
Flash droughts are relatively new to science, with the advancement of remote sensing technology during the past couple of decades helping reveal instances of soil rapidly drying out. This serves as the telltale sign of the onset of a flash drought and can make drought conditions appear seemingly out of the blue.

As the name suggests, flash droughts are short lived, usually lasting only a few weeks or months. But when they occur during critical growing periods, they can cause disasters. For example, in the summer of 2012, a flash drought in the central United States caused the corn crop to wither, leading to an estimated $35.7 billion in losses.

In this study, the scientists analyzed global hydroclimate data sets that use satellite soil moisture measurements to capture a global picture of flash drought and how it has changed during the past 21 years. The data showed that about 34%-46% of flash droughts came on in about five days. The rest emerge within a month, with more than 70% developing in half a month or less.

When they examined the droughts over time, they noticed the flash droughts happening more quickly. The study also revealed the importance of humidity and variable weather patterns, with flash droughts becoming more likely when there’s a shift from humid to arid conditions. That makes regions that undergo seasonal swings in humidity—such as Southeast Asia, the Amazon Basin, and the East Coast and Gulf Coast of the United States—flash drought hot spots.

Source  : APRIL 1, 2022

Annonce (Phys.org/news)

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