A team of UC San Diego-led atmospheric chemistry researchers moved closer to what is considered the "holy grail" of climate change science when it made the first-ever direct detection of biological particles within ice clouds.
The team, led by Kerri Pratt, a Ph.D. student of atmospheric chemistry Professor Kim Prather, who also holds appointments at Scripps Institution of Oceanography as well as the Department of Chemistry and Biochemistry at UCSD, sampled water droplet and ice crystal residues at high speeds from an aircraft flying through clouds in the skies over Wyoming in fall 2007. Analysis of the ice crystals revealed that they were made up almost entirely of either dust or biological particles such as bacteria, fungal spores and plant material. While it has long been known that microorganisms or parts of them get airborne and travel great distances, this study is the first to yield in-situ data on their participation in cloud ice processes.
Results of the Ice in Clouds Experiment Layer Clouds (ICE-L), funded by the National Science Foundation (NSF) and the National Center for Atmospheric Research (NCAR), appear May 17 in the advance online edition of the journal Nature Geoscience.
"If we understand the sources of particles that nucleate clouds and their relative abundance, then we can determine the impact of these different sources on climate," said Pratt.
The effects of tiny airborne particles called aerosols on cloud formation have been some of the most difficult aspects of weather and climate for scientists to understand. In the climate change science field, which derives many of its projections from computer simulations of climate phenomena, the actions of aerosols on clouds represent what scientists consider the greatest uncertainty in modeling predictions for the future.
"By sampling clouds in real time from an aircraft, these investigators were able to get information about ice particles in cl
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University of California - San Diego