HR: 0800h
AN: A51E-0844    [Abstracts]
TI: Investigations of the Physical and Chemical Properties of Free Tropospheric Ice Nuclei
AU: * Richardson, M
EM: mattr@chem.atmos.colostate.edu
AF: Colorado State University, Department of Atmospheric Science, Fort Collins, CO 80523
AU: DeMott, P
EM: pdemott@lamar.colostate.edu
AF: Colorado State University, Department of Atmospheric Science, Fort Collins, CO 80523
AU: Cziczo, D
EM: djcziczo@al.noaa.gov
AF: National Oceanic and Atmospheric Administration, Aeronomy Lab, Boulder, CO 80305
AU: Jimenez, J
EM: jose.jimenez@colorado.edu
AF: University of Colorado, Department of Chemistry, Boulder, CO 80309
AU: Dunlea, E
EM: edward.dunlea@colorado.edu
AF: University of Colorado, Department of Chemistry, Boulder, CO 80309
AU: Prenni, A
EM: prenni@lamar.colostate.edu
AF: Colorado State University, Department of Atmospheric Science, Fort Collins, CO 80523
AU: Brooks, S
EM: sbrooks@lamar.colostate.edu
AF: Colorado State University, Department of Atmospheric Science, Fort Collins, CO 80523
AU: Kreidenweis, S
EM: sonia@atmos.colostate.edu
AF: Colorado State University, Department of Atmospheric Science, Fort Collins, CO 80523
AU: Snider, J
EM: jsnider@uwyo.edu
AF: University of Wyoming, Department of Atmospheric Science, Laramie, WY 82071
AU: Petters, M
EM: petters@uwyo.edu
AF: University of Wyoming, Department of Atmospheric Science, Laramie, WY 82071
AU: Murphy, D
EM: murphyd@al.noaa.gov
AF: National Oceanic and Atmospheric Administration, Aeronomy Lab, Boulder, CO 80305
AU: Borys, R
EM: Randolph.Borys@dri.edu
AF: Desert Research Institute, Atmospheric Sciences Division, Reno, NV 89512
AU: McDade, C
EM: cemcdade@ucdavis.edu
AF: Crocker Nuclear Laboratory, University of California, Davis, CA 95616
AB: In spring of 2004 researchers from several institutions participated in INSPECT-II, a field campaign aimed at determining the physical and chemical properties of aerosols activating as ice nuclei (IN) under conditions present in mixed-phase and cold clouds. Studies were conducted at Storm Peak Laboratory located atop Mt. Werner (3210 m above MSL) in the northern Colorado Rocky Mountains. Emphasis of the study was on determining the impact of Asian dust on the concentrations of IN, but contributions from other aerosol sources were also expected. In this study, a continuous-flow diffusion chamber (CFDC) was used to activate IN. A counter-flow virtual impactor (CVI) located immediately downstream of the CFDC separated activated ice nuclei from inactive particles. Flow from the CVI was split between two aerosol mass spectrometers (Aerodyne's Aerosol Mass Spectrometer (AMS) and NOAA's Particle Analysis by Laser Mass Spectrometry (PALMS)) which evaluated the composition of the residual IN. These mass spectrometers also measured ambient particle composition. Additional measurements were made of the ambient aerosol population and included particle size distributions from 0.004 to 20 $\mu$m, particle hygroscopicity, cloud condensation nuclei activity and composition of bulk collections. This paper describes the experimental methodologies employed and provides some preliminary IN concentration data. These data are compared with data from INSPECT-I and with some of the measurements of the ambient aerosol population. These comparisons are used to draw inferences regarding the properties of the fraction of particles serving as ice nuclei.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0320 Cloud physics and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting