HR: 10:53h
AN: A32B-03    [Abstracts]
TI: Resolving discrepancies between observational and theoretical representations of the asymmetry parameter of atmospheric ice crystals
AU: * Garrett, T
EM: tim.garrett@utah.edu
AF: University of Utah, 135 S 1460 E Rm 819, Salt Lake City, UT 84112,
AB: The asymmetry parameter of ice crystals is a scattering property of primary interest to studies of the role of clouds in the earth's climate. Substantial effort has been devoted to ascertaining its value using both airborne sensors and theoretical calculations, However, observations and theory do not agree, even while the latter are employed almost exclusively in climate modeling and remote sensing applications. In general, observations indicate smaller values of the asymmetry parameter than theory, and a much weaker dependence on cloud particle size. In this review, it is argued that the discrepancy can be reconciled if it is considered that the scattering properties of atmospheric ice crystals are dominated by sub-crystal scale morphological features. The most likely candidate is ice crystal surface roughness.
DE: 3359 Radiative processes
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting