Dust particles from deserts promote ice formation in clouds.
Dust particles from deserts promote ice formation in clouds. This discovery highlights the importance of aerosols for understanding cloud behaviour, predicting precipitation, and assessing the role of clouds in climate change.
A new study shows that natural dust particles, swirling in from faraway deserts can cause clouds in Earth’s Northern Hemisphere to form ice crystals (or to glaciate). This subtle mechanism has major implications for climate projections.
Drawing on 35 years of satellite observations, an international research team led by ETH Zurich found that mineral dust—tiny particles swept up by the wind and carried into the upper atmosphere—can trigger the freezing of cloud droplets. This process is particularly important in northern regions, where clouds often form in a temperature range just below freezing.
“Where there’s more dust, clouds are much more likely to freeze at the top,” explains Diego Villanueva, a post-doctoral researcher for Atmospheric Physics at ETH Zurich and lead author of the study.
Read More: ETH Zurich
Image: The wind carries dust particles from the Sahara Desert great distances enabling ice cloud formation. (Image: Diego Villenueva Ortiz / ETH Zurich)
