HR: 1330h
AN: A22B-1066    [PDF]
TI: Biomass Burning Particles as Potential Ice Nuclei
AU: * Prenni, A J
EM: prenni@lamar.colostate.edu
AF: Colorado State University, Department of Atmospheric Science, Campus Delivery 1371, Fort Collins, CO 80523-1371
AU: DeMott, P J
EM: pdemott@lamar.colostate.edu
AF: Colorado State University, Department of Atmospheric Science, Campus Delivery 1371, Fort Collins, CO 80523-1371
AU: Kreidenweis, S M
EM: sonia@chem.atmos.colostate.edu
AF: Colorado State University, Department of Atmospheric Science, Campus Delivery 1371, Fort Collins, CO 80523-1371
AB: Biomass burning emissions account for massive amounts of gaseous and particulate matter in the atmosphere. Assessing these emissions and their climatic effects has been the focus of several major field campaigns. It has been shown that smoke particles act as efficient cloud condensation nuclei, which can affect precipitation and indirect radiative forcing. However, to date there have been no measurements aimed at characterizing ice-forming nuclei derived from biomass burning. Such measurements are critical for understanding cloud formation and precipitation processes throughout the troposphere. Measurements to determine the activity of biomass burning particles as ice nuclei are currently being conducted in our laboratory using the Colorado State University continuous flow thermal gradient diffusion chamber (CFDC). This instrument allows for continuous freezing measurements for free-floating particles at controlled temperatures, pressures, and humidities, relevant to both cumulus and cirrus clouds. Further, the CSU laboratory is equipped with a 50 m$^{3}$ containment vessel to allow for burning of vegetation and sampling of the resulting particles. Size-selective ice nucleation measurements have been conducted at temperatures relevant for homogeneous and heterogeneous ice nucleation. Preliminary results will be presented for smoke particles generated from a variety of biomass fuel sources. This work seeks to address the dearth of data needed to better understand and model the potential effects of biomass burning particulate matter on cold clouds and climate. Future work will also include pure compounds known to be abundant in biomass burning aerosol and covering a range of solubilities.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0320 Cloud physics and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting