HR: 13:55h
AN: SA33A-02    [Abstracts]
TI: Modeling of Mesospheric ice Particles:Challenges and Assessment of Current Capabilities
AU: * Rapp, M
EM: markusr@misu.su.se
AF: Department of Meteorology, Stockholm University, Stockholm, Sweden
AU: Thomas, G E
EM: thomas@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, CB 392, University of Colorado, Boulder, CO 80309 United States
AB: Considerable progress has been made in the past years concerning the experimental capabilities to observe mesospheric ice particles from space, from the ground, and in situ. These observations have provided a wealth of experimental data defining the properties of mesospheric ice particles like their global spatial and temporal occurrence patterns, their light scattering signatures, as well as their interaction with the charged part of the atmosphere, i.e., the ionosphere. Despite this progress regarding the observational data base, a quantitative description of related physical and chemical processes is still a challenging task due to uncertainties of several microphysical aspects concerning ice evolution in the harsh environment of the polar summer mesopause region. In the current paper, we discuss the key uncertainties regarding the microphysics of mesospheric ice particles including issues like current knowledge of the water vapor saturation pressure at mesopause temperatures, particle sedimentation characteristics, ice particle nucleation, and the effect of turbulent transport on the ice particle size distribution. The sensitivity of ice particle properties towards these uncertainties is assessed using the CARMA (=Community Aerosol and Radiation Model for Atmospheres) microphysical model. Mie scattering calculations using the simulated size distributions are compared to published characteristics of mesospheric ice particles observed from space and from the ground.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0320 Cloud physics and chemistry
DE: 0340 Middle atmosphere--composition and chemistry
DE: 2419 Ion chemistry and composition (0335)
DE: 3360 Remote sensing
SC: SPA-Aeronomy [SA]
MN: 2005 Joint Assembly