Related Research Areas
Atmospheric Composition

The formation of cirrus clouds in the upper troposphere depends on the number, size, and composition of ice-forming aerosols. Measurements of ice nuclei properties in the upper troposphere are rare, yet information on nucleation mechanisms is required to guide laboratory studies and constrain cloud models parameterizations. We propose to fly two single particle characterization instruments aboard the NASA WB-57 during MACPEX. The Particle Analysis by Laser Mass Spectrometry instrument (PALMS) measures aerosol composition and size in real time and has participated in several previous WB-57 campaigns. An electron microscope (EM) sampling array collects aerosols for offline quantitative analysis. An improved counterflow virtual impactor (CVI) inlet is proposed that is capable of sampling a larger fraction of ice crystals within mid-latitude cirrus than previous studies. Ice crystals D<50 microns are evaporated within the inlet, and the residual ice-forming nuclei are sent to PALMS and the EM array for characterization. Ice nuclei composition and size information addresses a principal science question of the MACPEX campaign. Additionally, aerosol composition measurements in clear air and cloud outflow regions can help characterize aerosol source regions and processing.

Project PI: Karl Froyd/NOAA Earth System Research Laboratory


Phone: (303) 497-4766


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Started: Sep 27, 2010

Last Activity: Jan 04, 2011


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