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Evolving landscape added fuel to Gobi Desert’s high-speed winds

ScienceDaily (January 8, 2020 )

A new study uncovers a previously undocumented relationship between erosion and wind speed

Titre : Evolving landscape added fuel to Gobi Desert’s high-speed winds

A new study uncovers a previously undocumented relationship between erosion and wind speed

ScienceDaily (January 8, 2020 )

Résumé
On February 28, 2007, harsh winds blew 10 train cars off a track running near China’s Hami basin, killing three passengers and seriously injuring two others. Hurricane-force gusts of 75 mph or more scour this basin every 15-20 days or so, on average, and can reach maximum speeds of more than 120 mph. A study published last week in Nature Communications has documented a new feedback loop that may have helped to make this basin in the Gobi Desert one of the windiest places in China.

Descriptif
The Hami basin may once have been covered in a fine, light-colored sediment, similar to California’s Death Valley. Within the past 3 million years, however, strong winds carried away those fine sediments, leaving behind a sea of gray and black rocks.

Using a weather and forecasting model, Abell and his colleagues studied how this change from light to dark landscape affected wind speeds in the basin. By absorbing more sunlight, the darker stones exposed by wind erosion heated up the air within the depression. The team found that the resulting differences in temperature between the depression and the surrounding mountains increased wind speeds by up to 25 percent. In addition, the amount of time the area experiences high wind speeds increased by 30 to 40 percent.

Thus, by changing how much sunlight the ground absorbs, wind erosion appears to have exacerbated wind speeds in this region. It’s the first time this positive feedback loop has been described and quantified, said Abell.

But it’s probably not the only example of its kind. The researchers think this interaction may have helped to shape other stony deserts in Australia, Iran, and perhaps even on Mars.

Story Source  : Earth Institute at Columbia University

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Page publiée le 22 juin 2021