In-situ detection of biological particles in cloud ice-crystals

AMS Citation:
Pratt, K. A., and Coauthors, 2009: In-situ detection of biological particles in cloud ice-crystals. Nature Geoscience, 2, 398-401, doi:10.1038/ngeo521.
Date:2009-06-01
Resource Type:article
Title:In-situ detection of biological particles in cloud ice-crystals
Abstract: The impact of aerosol particles on the formation and properties of clouds is one of the largest remaining sources of uncertainty in climate change projections. Certain aerosol particles, known as ice nuclei, initiate ice-crystal formation in clouds, thereby affecting precipitation and the global hydrological cycle. Laboratory studies suggest that some mineral dusts and primary biological particles-such as bacteria, pollen and fungi-can act as ice nuclei. Here we use aircraft-aerosol time-of-flight spectrometry to directly measure the chemistry of individual cloud ice-crystal residues (obtained after evaporation of the ice), which were sampled at high altitude over Wyoming. We show that biological particles and mineral dust comprised most of the ice-crystal residues: mineral dust accounted for ∼50% of the residues and biological particles for ∼33%. Along with concurrent measurements of cloud ice-crystal and ice-nuclei concentrations, these observations suggest that certain biological and dust particles initiated ice formation in the sampled clouds. Finally, we use a global aerosol model to show long-range transport of desert dust, suggesting that biological particles can enhance the impact of desert dust storms on the formation of cloud ice.
Peer Review:Refereed
Copyright Information:Copyright 2009 Author(s).
OpenSky citable URL: ark:/85065/d78916xp
Publisher's Version: 10.1038/ngeo521
Author(s):
  • Kerri Pratt
  • Paul DeMott
  • Jeffrey French
  • Zhien Wang
  • Douglas Westphal
  • Andrew Heymsfield - NCAR/UCAR
  • Cynthia Twohy
  • Anthony Prenni
  • Kimberly Prather
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