Regional Climate Model results in Pacific North America and the northern Columbia Basin

Regional Climate Model (RCM) projections from the North American Regional Climate Change Assessment Program (NARCCAP) and from Ouranos Consortium have been analysed over Pacific North America. Preliminary findings include skill of each RCM to reproduce general features of temperature and precipitation climatology over the region under large scale forcing at the boundaries by observations (NCEP2 reanalysis). In comparison to Global Climate Models, RCM results are in much better agreement with historical observations. In particular, the effects of complex topography on precipitation (windward and rainshadow areas) are much improved, as is the ability to capture the effects of elevation on temperature. At the sub-regional scale, however, large differences exist between models. The differences are explored – and compared to observations – by focusing in on the northern Columbia River Basin. Informed by the results of this comparison, RCM projections of future climate and hydrologic change are shown for the region. Finally, an analysis of extremes was conducted in collaboration with users (Columbia Basin Trust, Engineers Canada, and communities in the Columbia Basin). Projections of extremes inform vulnerability assessments of community infrastructure and adaptation planning.