HR: 08:15h
AN: A11D-02    [Abstracts]
TI: Insights into Stratospheric Dehydration Using Isotopes of Water
AU: Webster, C R
EM: Chris.R.Webster@jpl.nasa.gov
AF: NASA Jet Propulsion Laboratory, California Institute of Technology 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AU: * Gettelman, A
EM: andrew@ucar.edu
AF: National Center for Atmospheric Research, 1850 Table Mesa Dr, Boulder, CO 80305 United States
AB: An analytic model of transport and microphysics in the tropical tropopause layer (TTL) is extended to include stable isotopes of water. The model, running along trajectories, is tested against in-situ and satellite observations of HDO and H$_2$$^{18}$O. The model is able to reproduce the range of isotopic depletions observed in the data, and reproduce individual episodes that mirror or depart from Rayleigh fractionation processes. The results indicate that water substance in the upper troposphere does not follow a Rayleigh distillation model due to the presence of detrained ice in the TTL. The results are also used to illustrate that stratospheric abundances of stable isotopes of water can be understood based on known isotopic physics, convective detrainment of ice and gradual dehydration.
DE: 3362 Stratosphere/troposphere interactions
DE: 3314 Convective processes
DE: 1040 Isotopic composition/chemistry
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting