CMIP5 Global Climate Model Performance Evaluation and Climate Scenario Development over the South-Central United States

Abstract:

Future climate change projections from Global Climate Models (GCMs) are the primary drivers of regional downscaling and impacts research – from which relevant information for stakeholders is generated at the regional and local levels. Therefore understanding uncertainties in GCMs is a fundamental necessity if the scientific community is to provide useful and reliable future climate change information that can be utilized by end users and decision makers.

Two different assessments of the Coupled Model Intercomparison Project Phase 5 (CMIP5) GCM ensemble were conducted for the south-central United States. The first was a performance evaluation over the historical period for metrics of near surface meteorological variables (e.g., temperature, precipitation) and system-based phenomena, which include large-scale processes that can influence the region (e.g., low-level jet, ENSO). These metrics were used to identify a subset of models of higher performance across the region which were then used to constrain future climate change projections. A second assessment explored climate scenario development where all model climate change projections were assumed equally likely and future projections with the highest impact were identified (e.g., temperature and precipitation combinations of hottest/driest, hottest/wettest, and highest variability).

Each of these assessments identify a subset of models that may prove useful to regional downscaling and impacts researchers who may be restricted by the total number of GCMs they can utilize. Results from these assessments will be provided as well as a discussion on when each would be useful and appropriate to use.