Using Clustered Climate Regimes to Analyze and Compare Predictions from Fully Coupled General Circulation Models

Ensemble Cluster Evolution, 5 Year Running Average, Random Colors - 32 Clusters

Five year running average of cluster frequency for regimes exhibiting significant global land area changes in the ensemble mean where the clusters are defined as follows:

32	Antarctic/Greenland Fall/Spring #1
9	Desert Summer (Hottest and Driest)
7	Antarctic/Greenland Fall/Spring #2
1	Desert Winter
26	Siberian/Canadian Winter
6	Antarctic Winter #1 (Coldest and Driest)
11	Antarctic/Greenland Summer

Multivariate Spatio-Temporal Clustering (MSTC) was applied to the monthly time series output from five 99-year Business-As-Usual (BAU) transient simulations of the Parallel Climate Model (PCM) from 2000-2098

MSTC establishes an exhaustive set of recurring climate regimes which form a "skeleton" through the "observations" (model output) throughout the occupied portion of the climate phase space formed by the characteristics being considered. Temperature, precipitation, and soil moisture were included in this analysis.

Strong predicted interannual trends were revealed in this analysis, including an increase in global desertification; a decrease in the cold, dry high latitude conditions typical of North American and Asian winters; and significant warming in Antarctica and western Greenland.

MSTC is a powerful tool for model developers and environmental decision-makers who wish to understand long, complex time series predictions of models.

MSTC facilitates direct comparison of ensemble members, ensemble and temporal averages, as well as observational data since the derived climate regimes provide a basis for comparison.

Random (top) and similarity colored (bottom) animations of the B05.12 ensemble member in terms of the common climate regimes shown at right. Click on the desired image above to view the animation.

Common climate regimes or states statistically defined in terms of three variables--temperature, precipitation, and soil moisture--for all five BAU transient simulations taken together.

References:

Hoffman, Forrest M., William W. Hargrove, David J. Erickson, and Robert J. Oglesby. August 3, 2005. "Using Clustered Climate Regimes to Analyze and Compare Predictions from Fully Coupled General Circulation Models." Earth Interactions, 9(10): 1-27, doi:10.1175/EI110.1. [ PDF ]

Graphics and animations are available at http://www.climatemodeling.org/pcm/.

Research partially sponsored by the U.S. Department of Energy, Office of Science, Biological and Environmental Research Programs. This research used resources of the National Center for Computational Sciences at Oak Ridge National Laboratory which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. Support was also provided by a research and development grant from the Science Directorate of NASA/MSFC.