Changes in the strength of the Brewer-Dobson circulation in a simple AGCM

Abstract

A simple general circulation model is used to explore the response of the Brewer-Dobson circulation to warming of the tropical troposphere typically associated with greenhouse gas warming in climate models. The strength of the modeled Brewer-Dobson circulation increases in response to tropospheric tropical warming. The tropical warming causes the midlatitude baroclinicity to increase, which leads to an increase in the wave activity at synoptic and planetary scales. Increased wave propagation from the troposphere causes stronger EP flux convergence in the stratosphere. The EP flux convergence drives a stronger Brewer-Dobson circulation via downward control arguments. These results are compared to other recent GCM studies. Copyright 2005 by the American Geophysical Union.