The effect of CO₂ concentration on the frequency of blocking in a general circulation model coupled to a simple mixed layer ocean model.

The effect of a doubling of atmospheric CO₂ on the characteristics of the 500 mb height field and persistent height anomalies associated with blocking phenomena are investigated in two experiments with the NCAR Community Climate Model (CCM) coupled to a simple ocean mixed layer. This version of the CCM with a seasonal cycle, computed hydrology and the simple mixed layer ocean produces a somewhat improved simulation compared with earlier model versions in spite of a lack of ocean heat transport and overextensive sea ice.-from Authors