Simulated and Observed Atmospheric Circulation Patterns Associated with Extreme Temperature Days over North America

Tuesday, May 13, 2014 - 07:00
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Circulation patterns associated with extreme temperature days over North America as simulated by a suite of climate models are compared with those obtained from observations. Seventeen coupled atmosphere-ocean general circulation models obtained from the fifth phase of the Coupled Model Intercomparison Project are used. Several metrics used to systematically describe circulation patterns associated with extreme temperature days are applied to both the observed and model simulated data. In general, the multi-model ensemble resembles the observed patterns well, especially in areas removed from complex geographic features (e.g. mountains and coastlines). Individual model results vary; however the majority of models capture the major features observed. The multi-model ensemble captures several key features including regional variations in the strength and orientation of atmospheric circulation patterns associated with extreme temperature, both near the surface and aloft, as well as variations with latitude and season. The results from this work suggest that these models can be used to comprehensively examine the role that changes in atmospheric circulation will play in projected changes in temperature extremes due to future anthropogenic climate warming.