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Understanding rare rain events in the driest desert on Earth

Phys.org/news (JANUARY 18, 2022)

Titre : Understanding rare rain events in the driest desert on Earth

Phys.org/news (JANUARY 18, 2022)

Présentation
In the enduring dryness of the Atacama Desert in northern Chile where the average rainfall is as low as 5 millimeters per year, rare rain events can come swiftly and intensely. They shape the landscape and provide precious moisture to plants and other species that otherwise adapted to extended dry spells or harvesting coastal fog. Intense rain events like those seen in the Atacama are known to be associated with so-called moisture conveyor belts, which are high-altitude atmospheric phenomena known for transporting large volumes of water vapor. However, whether or not moisture conveyor belts are responsible for the Atacama’s intense rain events has yet to be shown.

In a new study, Böhm et al. explain the atmospheric mechanisms behind the wettest of these precipitation events and propose that the water travels from the tropical Amazon across oceans and mountains to reach the desert. The research shows that 40%–80% of the total precipitation that occurs between the coast and the Andean foothills is associated with moisture conveyor belts.

Rain events related to moisture conveyor belts can be devastating for local microbial species adapted to dry conditions, the authors say, but they could play a role in the germination of the blooming desert—an explosion of colorful wildflowers that occurs in the Atacama every five to seven years. The authors’ understanding of the processes behind these rare events could change how scientists understand past and future climates in the region.

Source  : Emily Cerf, American Geophysical Union

Annonce (Phys.org/news)

Page publiée le 13 janvier 2023