May 19, 2009
Biological particles found in high clouds
U.S. scientists say they've made the first direct observations of biological particles in high-altitude clouds.
A team of atmospheric chemists led by Kimberly Prather and Kerri Pratt of the Scripps Institution of Oceanography at the University of California-San Diego sampled water droplet and ice crystal residues at high speeds while flying through clouds in the skies over Wyoming.
The scientists said their findings suggest biological particles that get swept up in dust storms help to induce the formation of cloud ice, and that their region of origin makes a difference. For example, they said, evidence is increasingly suggesting that dust transported from Asia could be influencing North American precipitation.
The National Science Foundation and National Center for Atmospheric Research-funded study is reported in the early online edition of the journal Nature Geoscience.