HR: 09:00h
AN: SA51A-03 INVITED     [Abstracts]
TI: Trends in Mesospheric Dynamics and Chemistry: Simulations With a Model of the Entire Atmosphere
AU: * Brasseur, G P
EM: brasseur@dkrz.de
AF: Max Planck Institute for Meteorology, Bundesstrasse, 53, Hamburg, Ham 20146 Germany
AB: The cooling resulting from infrared CO2 radiative transfer is a major contribution to the energy budget of the middle atmosphere and thermosphere. The rapid increase of the atmospheric CO2 concentration resulting from anthropogenic emissions is therefore expected to lead, in general, to a substantial cooling in this height range. This can potentially be counteracted by heating due to absorption of near infrared radiation by CO2. Changes in ozone as a consequence of increasing methane and water vapor may also have an impact on the energy budget as dynamical changes caused by increased tropospheric temperatures. By means of numerical simulations with a general circulation and chemistry model of the entire atmosphere we will address the following questions: 1.) Can state-of-the-art atmospheric modeling explain the mesospheric temperature trends observed during the last decades? 2.)Which part of the temperature changes resulting from an increase of atmospheric CO2 is caused by local changes in the radiative budget and which part is influenced by remote dynamical effects? The model used is the newly developed Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA) that resolves the atmosphere from the Earth's surface up to about 250 km altitude, and is based on the 3-D dynamics from the ECHAM5 general circulation model and the chemistry scheme from MOZART-3. Results from different time slice experiment representative of years 1970 and 2000, and for a doubling of CO2 will be presented.
DE: 0340 Middle atmosphere--composition and chemistry
DE: 1610 Atmosphere (0315, 0325)
DE: 3337 Numerical modeling and data assimilation
SC: SPA-Aeronomy [SA]
MN: 2005 Joint Assembly