HR: 1340h
AN: SA53A-1161    [Abstracts]
TI: Sensitivity of Trace Species to Transport and Diffusion Near the Mesopause
AU: * Smith, A K
EM: aksmith@ucar.edu
AF: NCAR/ACD, P.O. Box 3000, Boulder, CO 80307 United States
AU: Marsh, D R
EM: marsh@ucar.edu
AF: NCAR/ACD, P.O. Box 3000, Boulder, CO 80307 United States
AU: Richter, J H
EM: beres@ucar.edu
AF: CIRES, University of Colorado, Boulder, CO 80309 United States
AB: Transport in the mesopause region is complicated because there are a number of different processes that make important contributions; which ones are dominant depends on altitude, latitude, and time scale. The dynamical processes include advection by gravity waves, tides, planetary waves, and the mean meridional circulation; eddy diffusion associated with breaking gravity waves; and molecular diffusion. While a range of observations are available for tides and planetary waves, both the diffusion rates and the mean circulation are difficult to determine observationally. In general, the sensitivity of a trace species to transport depends on the strength of its gradients and its photochemical lifetime. The 3-dimensional ROSE model is used to determine which species are most sensitive to which transport and diffusive processes. Observations of these species can then provide a constraint on the values of the diffusion rates, mean vertical velocity, etc.
DE: 0340 Middle atmosphere: composition and chemistry
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005