Eco-briefs | Aerosols from one side of world influence rainfall on the other

Bag design by Zoe Burton
Boulder Weekly Staff | Boulder Weekly

A field study conducted by researchers from the National Oceanic and Atmospheric Administration (NOAA) and the University of California San Diego (UCSD) shows that dust and microorganisms help spur precipitation, which California counts on for its water supply. The recently released CalWater field study traced aerosols from the Sahara desert all the way to the Sierra Nevada mountains.

The fact that winds can carry aerosols from continent to continent at high altitudes is not news. What is news, however, is that although pollution particles can suppress precipitation, dust and biological aerosols tend to enhance precipitation-forming processes in the Sierra Nevada mountains.

“We were able to show dust and biological aerosols that made it as far as the Sahara were incorporated into the clouds to form ice, then influenced the formation of the precipitation in California,” says Jessie Creamean, a postdoctoral associate at NOAA’s Earth System Research laboratory in Boulder, according to a report published on the NOAA website.

CalWater researchers acknowledged that it is a major challenge to separate weather patterns, atmospheric changes and the original sources of cloud seeds on precipitation processes. They added that future studies are necessary to further identify which aerosols are conducive to precipitation formation and which aerosols stifle its production, according the NOAA report.

“This state-funded study in cooperation with NOAA will help us understand how small particles in the air affect precipitation and hydropower generation,” Energy Commission Chair Robert Weisenmiller says. “Additionally, this information will be useful in estimating the effects of our changing climate.”

Abby Faires


Designs submitted by Blair Stapp and Zoe Burton to Boulder’s digital town hall website have been selected to print on 30,000 reusable bags later this year. The city plans to offer the bags to low-income residents and seniors, when a 10-cent fee on paper and plastic bags at the checkouts of retail grocers goes into effect on July 1.

— Abby Faires

Bag design by Blair Stapp