Comparison of Global and Regional Model Climate Changes in the NARCCAP Suite of Models

The North American Regional Climate Change Assessment Program (NARCCAP) is an international program that is serving the climate scenario needs of the United States, Canada, and northern Mexico. We have systematically investigated the uncertainties in regional scale projections of future climate and producing high resolution climate change scenarios using multiple regional climate models (RCMs) and multiple global model responses by nesting the RCMs within atmosphere ocean general circulation models (AOGCMs) forced with a medium-high emissions scenario, over a domain covering the conterminous US, northern Mexico, and most of Canada. The project also includes a validation component through nesting the participating RCMs within the NCEP reanalysis R2. The basic spatial resolution of the RCM simulations is 50 km. This program includes six different RCMs. Four different AOGCMs provide boundary conditions to drive the RCMS for 30 years in the current climate and 30 years for the mid 21st century. All 12 sets of current and future simulations have been completed. The comparative climate changes for sub-regions of the domain from the AOGCMs, the RCMs and the full suite of CMIP3 results will be presented.