HR: 09:00h
AN: A51F-07    [Abstracts]
TI: The modelled impact of changes in the CO₂ concentration on the middle and upper atmosphere: sensitivity to gravity wave activity and parameterization
AU: * Cnossen, I
EM: ic35@ion.le.ac.uk
AF: Radio and Space Plasma Physics Group, University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
AU: Arnold, N
EM: nfa1@ion.le.ac.uk
AF: Radio and Space Plasma Physics Group, University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
AU: Harris, M
EM: matthew@apl.ucl.ac.uk
AF: Atmospheric Physics Laboratory, University College London, Gower Street, London, WC1E 6BT, United Kingdom
AU: Yigit, E
EM: erdal@apl.ucl.ac.uk
AF: Atmospheric Physics Laboratory, University College London, Gower Street, London, WC1E 6BT, United Kingdom
AB: Cooling of the middle and upper atmosphere by CO₂ is dependent on the temperature of the ambient atmosphere. Since the temperature structure is partly controlled by the residual circulation, driven mostly by the dissipation of gravity waves, CO₂ cooling is expected to be dependent on the strength of the residual circulation, and thereby on the gravity wave activity. Also, the dissipation process of gravity waves is dependent on the temperature of the atmosphere they are propagating through, and this dependence is reflected differently in different gravity wave parameterization schemes. This may have important consequences for temperature trends due to changes in the CO₂ concentration as calculated by middle and upper atmospheric GCMs. Therefore we will show, using the Coupled Middle Atmosphere and Thermosphere model 2 (CMAT2), how such trends depend on the gravity wave parameterization that is used and the gravity wave activity that is assumed by the model.
DE: 0325 Evolution of the atmosphere (1610, 8125)
DE: 0340 Middle atmosphere: composition and chemistry
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
DE: 0350 Pressure, density, and temperature
DE: 0355 Thermosphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting