Incorporation of Climate Change into Design Storms: The Challenges

Historical storms producing heavy rainfall are often used to assist in the design of infrastructure. Such “design storms” are used in models to test the engineering limits of infrastructure when experiencing extreme precipitation. Many areas of the U.S. have experienced recent increases in the number and intensity of extreme precipitation events. Temperatures are projected to increase across all areas of the CONUS due to increasing greenhouse gas concentration and this will lead to increases in atmospheric moisture content due to the Clausius-Clapeyron relationship. As a result, further increases in extreme precipitation can be expected. Stakeholders seek to understand how these large-scale atmospheric changes will impact local and regional precipitation intensity and spatial distribution. Statistically downscaled climate projections, such as Localized Constructed Analogs (LOCA), provide local trends for changing moisture parameters, but cannot provide information on the detailed precipitation dynamics of a particular extreme event. Regional climate modeling for specific design storms projected under global warming scenarios may be able to fill in this data gap. This project investigates the challenges of modeling future design storms under a pseudo-global warming regime. In addition, this project showcases how the combination of regional climate modeling and statistical downscaled projections can better inform stakeholders in preparing for future extreme precipitation events.