Dust in the clouds: Cirrus clouds form around mineral dust and metallic particles

By davedahl, March 3, 2015

Cirrus clouds influence global climate, cooling the planet by reflecting incoming solar radiation and warming it by trapping outgoing heat. Understanding the mechanisms by which these clouds form may help scientists better predict future climate patterns. Scientists have now identified the major seeds on which cirrus clouds form.

Now an interdisciplinary team from MIT, the National Oceanic and Atmospheric Administration (NOAA), and elsewhere has identified the major seeds on which cirrus clouds form. The team sampled cirrus clouds using instruments aboard high-altitude research aircraft, analyzing particles collected during multiple flights over a nine-year period. They found that the majority of cloud particles freeze, or nucleate, around two types of seeds: mineral dust and metallic aerosols.

“We think we’re really looking at the seed, the nucleus of these ice crystals,” says Dan Cziczo, an associate professor of atmospheric chemistry at MIT. “These results are going to allow us to better understand the climatic implications of these clouds in the future.”

The articles around this NASA research fail to note two important facts: A) These clouds are actually created by aircraft, as is rather obvious in this photo one article used; and B) the cloud nuclei they discuss– “mineral dust and metallic aerosols”– are the ingredients used widely in cloud-seeding flares used for weather modification in the US and many other countries… more specifically potassium iodide, silver nitrate, aluminum, strontium and magnesium.

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