At least a few times a year, strong and persistent winds from the south drive Saharan dust north toward Europe, as recent research explains. Two such events in 2021 ‘led to snow darkening by dust deposition over the Alps with 40% decrease in snow albedo’, among other effects. NASA says the dust plays a major role in Earth’s climate and biological systems, absorbing and reflecting solar energy and fertilizing ocean ecosystems with iron and other minerals that plants and phytoplankton need to grow. A slight positive trend in the frequency of such events since 1980 is suggested to be related to the El Niños in the period. The research paper hints at the need for climate models to take these events into account.
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On March 15, 2022, a plume of Saharan dust was blown out of North Africa and across the Mediterranean into Western Europe, says NASA’s Earth Observatory.
The dust turned skies orange, blanketed cities, impaired air quality, and stained ski slopes.
The plume was driven by an atmospheric river arising from Storm Celia, which brought strong winds, rain, and snow to the Canary Islands.
Atmospheric rivers, normally associated with extreme moisture, can also carry dust.
“You can think of them as the confluence of a dust river and a water vapor river within a single storm environment,” said Bin Guan, an atmospheric scientist at NASA’s Jet Propulsion Laboratory and the University of California, Los Angeles.
“The same atmospheric dynamics that give rise to a water vapor river—specifically strong winds—can act to pick up and transport dust as the storm moves across desert areas.”
Over the past four decades, 78 percent of atmospheric rivers over northwestern Africa have led to extreme dust events over Europe, according to research by Guan and colleagues.
Such “aerosol atmospheric rivers”—a term recently introduced in a NASA-led study that refers to narrow, elongated regions of extreme aerosol mass transport—can play an important role in climate and air quality around the world.
Continued here.
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NASA Earth Observatory — Aerosols: Tiny Particles, Big Impact
via Tallbloke’s Talkshop
March 19, 2022 at 04:24AM
Iowa Climate Science Education 