Dust and other airborne particles’ effect in the atmosphere is “one of the most important problems we need to solve in order to provide better predictions of climate,” said climate scientist Jasper Kok of the National Center for Atmospheric Research in Boulder, Colorado. Other researchers suspect current models also neglect a large fraction of the climate-warming dust that clogs the skies after dust storms.
Most climate models use dust data from satellites that measure how many particles of different sizes are suspended in the atmosphere. These measurements reveal an abundance of tiny clay particles roughly 2 micrometers across (about one-third the width of a red blood cell), which can reflect sunlight back into space and cool the planet.
But satellites may be missing larger particles, called silts, which don’t hang around in the air as long. Silts up to 20 micrometers in diameter can act as a warm blanket to trap heat inside the Earth’s atmosphere.
To figure out how much clay and silt is actually kicked up from the Earth’s deserts, Kok turned to a well-studied problem in physics: how glass breaks.
Cracks spread through breaking glass in specific patterns, creating predictable numbers and sizes of glass shards. The final distribution of small, medium and large glass fragments follows a mathematical law called scale invariance.
“It shows up all across nature, from asteroids to atomic nuclei,” Kok said. “It’s really just beautiful.”
In a paper published Dec. 28 in the Proceedings of the National Academy of Sciences, Kok showed that the physics of how dust clumps break apart is similar to glass breaking.
Soil scientists have long known that dust clumps act like brittle materials, and physicists have well-tested mathematical descriptions of how brittle materials break. “But no one had put one and two together,” Kok said.
Read more at Wired
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