HR: 17:45h
AN: A54B-08    [Abstracts]
TI: Laboratory Studies of Ice Nucleation on Organic Aerosol Surfaces
AU: * Pathak, S K
EM: shashi.pathak@mcgill.ca
AU: Ariya, P
EM: parisa.ariya@mcgill.ca
AB: Ice clouds play a key role in governing the Earth's radiative balance and in regulating the climate system. However, the chemistry and microphysics of ice surfaces and microphysical mechanisms in ice clouds are still unexplored, despite their dominant role in global climate change. Now, it has become apparent that atmospheric aerosols contain significant amounts of organic material and substantially impact the formation of natural clouds. It is believed that clouds formed in supersaturated environments may incorporate a heterogeneous component of particle nature, alternatively may freeze homogeneously on pre-existing supercooled liquid droplets. In this paper, we provide an experimental approach to ice nucleation by supercooled aqueous solutions of dicarboxylic acids at higher temperatures than that required for homogenous freezing thresholds. Present results suggest that low molecular weight dicarboxylic acids may initiate ice nucleation in the atmosphere thereby may play an important role in the formation of cloud particles. Thus, the possibility of ice formation by these compounds can not be ruled out, which in turn may influence the radiative forcing by atmospheric aerosols, however, this data is currently lacking in climate models.
DE: 1610 Atmosphere (0315, 0325)
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0320 Cloud physics and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting