[Tiimes-extended] Seminar by Kerri Pratt, 11 September 2008, 10:30 a.m.

[Teresa Rivas]

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Kerri A. Pratt^1 , Cynthia H. Twohy^2 , Kimberly A. Prather^1*

 

^1 Department of Chemistry and Biochemistry, University of California, 
San Diego, La Jolla, CA 92093 ^2 Department of Oceanic and Atmospheric 
Sciences, Oregon State University, Corvallis, OR 97331

 

 

 

*Flight-based Measurements of the Role of Aerosol Chemistry on Cloud 
Formation Using Single-Particle Mass Spectrometry*

 

 

The overall impacts of aerosol particles on cloud formation and 
properties represent the largest single source of uncertainty in 
predicting future climate change.  The vast majority of our knowledge of 
cloud nuclei is based on ground-based measurements and links between 
bulk aerosol chemistry and the number of measured cloud condensation 
nuclei (CCN).  In contrast, direct flight-based measurements of 
individual cloud droplets and ice crystals indicate which particles 
actually do form clouds, providing improved insight into the role of 
aerosol chemistry on CCN and ice nuclei (IN).  During the 2007 Ice in 
Clouds Experiment -- Layer Clouds (ICE-L), the size-resolved chemistry 
of individual cloud droplets and ice crystals were directly sampled and 
characterized in real-time using a counterflow virtual impactor in 
series with the recently-developed aircraft aerosol time-of-flight mass 
spectrometer (A-ATOFMS) during flight-based measurements aboard the 
NCAR/NSF C-130.  In particular, orographic wave clouds and upslope storm 
clouds were studied over Wyoming, Colorado, Nebraska, and South Dakota; 
mineral dust, dry lake bed salts, biological material, biomass burning 
particles, organic carbon, and elemental carbon were all found within 
the studied clouds.  These ICE-L A-ATOFMS results represent the first 
aircraft-based, single-particle dual-polarity mass spectrometry 
measurements, providing an increased understanding of single-particle 
mixing state of both refractory and non-refractory species with respect 
to altitude, cloud condensation nuclei, and ice nuclei. 

 

        Thursday, 11 September 2008                       Foothills Lab

        10:30 a.m. (refreshments at 10:00)               Room 1022

 

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/For more information, contact Teresa Rivas, ext 1437 or rivas at ucar.edu/

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______________________
Teresa Rivas
Administrator TIIMES
303-497-1437

http://www.tiimes.ucar.edu

NCAR
The Institute for Integrative & Multidisciplinary Earth Studies (TIIMES)
P.O. Box 3000
FL1-2024
Boulder, CO 80307-3000

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