HR: 09:06h
AN: SA51C-05 INVITED     [Abstracts]
TI: Dynamical influences on CO2 in the MLT: global model calculations.
AU: * Richter, J H
EM: beres@ucar.edu
AF: CIRES/University of Colorado, 216 UCB, Boulder, CO 80309 United States
AU: Smith, A K
EM: aksmith@ucar.edu
AF: ACD/NCAR, BOX 3000, Boulder, CO 80307 United States
AU: Garcia, R R
EM: rgarcia@ucar.edu
AF: ACD/NCAR, BOX 3000, Boulder, CO 80307 United States
AB: Carbon dioxide concentrations in the mesosphere and lower thermosphere (MLT) are driven by molecular diffusion, eddy diffusion from breaking gravity waves, advection by the mean circulation, chemical production and loss. In this talk we primarily examine the effects of eddy diffusion and advection on CO2 in the MLT using two global models: ROSE and WACCM. ROSE is a mechanistic dynamical and chemical model of the middle and upper atmosphere, whereas WACCM (Whole Atmosphere Community Climate Model) is a general circulation model extending from the earth's surface to the thermosphere with interactive chemistry. We present a detailed budget of CO2 forcings as a function of latitude and season, and examine the dependence of CO2 on assumptions made about gravity waves, in particular the Prandtl number. Using WACCM, we also explore the relation between localized regions of gravity wave activity and CO2 concentrations in the MLT.
DE: 0340 Middle atmosphere: composition and chemistry
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
DE: 0355 Thermosphere: composition and chemistry
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005