HR: 11:20h
AN: A12A-05    [Abstracts]
TI: Changes in the strength of the Brewer-Dobson circulation in a simple AGCM
AU: * Eichelberger, S J
EM: seich@atmos.washington.edu
AF: University of Washington, Department of Atmospheric Sciences Box 351640, Seattle, WA 98195-1640 United States
AU: Hartmann, D L
EM: dennis@atmos.washington.edu
AF: University of Washington, Department of Atmospheric Sciences Box 351640, Seattle, WA 98195-1640 United States
AB: Recent modelling work using the UK Met Office's Unified Model has shown that the strength of the Brewer-Dobson circulation increases in an double CO2 climate. A dynamical explanation for this strengthening is not yet well established. In order to find such an explanation, we use a simple general circulation model to investigate changes to the Brewer-Dobson circulation under different climate change scenarios. The model is a dry, primitive-equation model on a sphere which is forced via Newtonian relaxation of the temperature field towards radiative equilibrium values. As a first proxy of a double CO2 climate, we simply increase the radiative relaxation timescale in the stratosphere. Additional climate change simulations are constructed by changing the radiative equilibrium temperature field to values consistent with a double CO2 climate. Results from these model runs will be compared against a control case which is representative of current January mean conditions. The role of planetary waves will be discussed, as well as the importance of the subtropical jet structure.
DE: 3362 Stratosphere/troposphere interactions
DE: 3319 General circulation
DE: 1610 Atmosphere (0315, 0325)
DE: 1620 Climate dynamics (3309)
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting