Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023)

As Canada’s climate evolves, a better understanding of the patterns of precipitation extremes is critical. Engineers use charts that track the historic intensity, duration, and frequency of rainfall events to ensure their designs meet drainage standards. Frequently engineers use outdated weather station datasets that are geographically distant to their design projects. The Proponent created a tool that interpolates these charts, known as IDF curves, between weather stations for the Ontario Ministry of Transportation (MTO). The proposed research program expands and improves upon this work by confirming time trends in the historic data and extrapolating the results to build a climate change model for precipitation. The Proponent’s research will enable Canadian engineers to design infrastructure projects based on geographically-corrected precipitation patterns that will stay relevant for the entire design life of their projects, and improve scientific understanding of Canada’s regional climatological processes.

IDF extrapolation creates a solid basis for forecasting. The Intergovernmental Panel on Climate Change Special Report on Extreme Events (IPCC SREX) states that projected rises in temperature are virtually certain and it is likely that the frequency of heavy precipitation will increase. This research quantifies uncertainty and allows regulators and designers to refine their confidence limits by factoring regional complexities into their projections.

The key variables in this problem are extreme precipitation, extreme temperature, and time. The Clausius-Clapeyron Rate (CCR) is a theoretical ratio linking extreme precipitation and extreme temperature. As temperatures rise, precipitation rises between 5.9% and 7.7% per degree Celsius. Temperature is an excellent covariate not only because of its relationship to precipitation, but also because of the reliability of temperature projections.

To expand the Proponent’s research across Canada is complex. Geographic factors such as mountains introduce new problems. The Proponent will develop regional equations to weigh these factors differently. Then, factoring time and temperature, and using the CCR, the Proponent will project precipitation extremes across the country.

This research will provide objectivity and consistency for infrastructure planning. It will grant valuable insight for applying IDF interpolation and projection to new regions, not just in Canada, but globally. It will save engineers design time, reduce the risk of costly project over and under design, and save millions annually for Canadian infrastructure construction. The research will also aid future hydrological and atmospheric research, as it will improve the scientific understanding of regional relationships between temperature and precipitation over time.