HR: 0800h
AN: A21A-0718    [Abstracts]
TI: The vapor pressures of supercooled water and ice
AU: * Murphy, D M
EM: Daniel.M.Murphy@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305 United States
AB: The vapor pressures of supercooled water and ice are reviewed with an emphasis on atmospheric applications. Surprisingly, none of the commonly used parameterizations for the vapor pressure of supercooled water were originally considered valid below the freezing point. In addition, the World Meteorological Organization definition of the vapor pressure of supercooled water contains a typographical error. Recent data on the molar heat capacity of supercooled water are used to derive its vapor pressure. Still, the uncertainty is such that measurements of the deliquescence and freezing behavior of aerosol particles are beginning to be limited by uncertainties in the thermodynamics of supercooled water. The vapor pressure of ice is better known and the experimental data are in good agreement with a derivation from the Clapeyron equation. Below about 200 K the different vapor pressures of hexagonal and cubic ice need to be considered.
DE: 1655 Water cycles (1836)
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0320 Cloud physics and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting