RESPONSES OF A GLOBAL CGCM TO CO2 INCREASE

The responses of the climate system to increase of atmospheric carbon dioxide(CO)arestudied by using a new version of the Bureau of Meteorological Research Centre(BMRC)globalcoupled general circulation model(CGCM).Two simulations are run:one with atmospheric COconcentration held constant at 330 ppm,the other with a tripling of atmospheric CO(990 ppm).Results from the 41-year control coupled integration are applied to analyze the mean state,seasonal cycle and interannual variability in the model.Comparisons between the greenhouseexperiment and the control experiment then provide estimations of the influence of increased COon climate changes and climate variability.Especially discussed is the question on whether theclimate changes concerned with COinerease will impact interannual variability in tropical Pacific,such as ENSO.