Application Based Assessments Using Regional Atmospheric Models Over the Western United States to Inform Mitigation Strategies in a Changing Environment

Abstract

Regional climate change impact assessments require location-specific information. To be considered useful to decision-makers and stakeholders, information within impact assessments must have sufficient resolution, robust uncertainty characterization, and fit the application’s decision-making paradigm. The present study was performed for specific applications targeted at mitigating negative impacts of climate change, for example, renewable energy production, water resource management, and hazards from extreme precipitation events. In Appendix A, we incorporate forecast aerosols into operational solar energy forecasts. Using GEOS-5 forecasts of aerosol optical depth in day-ahead direct normal irradiance forecasts reduced error by ~20% compared to forecasts using an aerosol climatology. For Appendix B, we modify a tool that generates historical maps of precipitation by enhancing the regression framework it uses and adding ancillary data from a high-resolution numerical weather prediction model. We include short-lead precipitation data from the HRRR model in the regression calculations and show that the new product matches out-of-sample observations more closely than a regression formed using station observations only. Appendix C uses convection-permitting climate simulations to assess projected changes to extreme daily and hourly North American Monsoon precipitation. We find extreme hourly precipitation intensities are projected to increase at a greater than Clausius-Clapeyron rate for the next two decades in Arizona. The results of these studies can contribute and inform mitigation strategies into the 21st century.