Uncertainty Characterization and Delineation of Nonstationarity in Intensity-Duration-Frequency Curves of Precipitation Relevant for Infrastructural Design

Abstract:

Understanding the degree of stationarity in intensity-duration-frequency (IDF) curves of precipitation extremes relates to the design and maintenance of hydraulic infrastructures and hence to flood resilience. Statistical analysis of observations and climate models forced with projected emissions scenarios point to more frequent and intense precipitation extremes at global and century scales. A statistical delineation of changes in IDF curves at scales relevant for infrastructures has proved elusive, owing to significant spatial variability, data and model quality, and estimation uncertainties. The contribution of climate internal variability, in addition to thresholds and intermittences, has not received much attention in the literature. However, this relatively irreducible component of the uncertainty may dominate for decadal planning horizons, especially at the spatial scales relevant for hydraulic infrastructures. A characterization of the irreducible uncertainties, which in turn yields an envelope of plausible scenarios, may need to be a critical pathway for resilient engineering. Statistical and information theoretic methods are developed or adapted from the literature to characterize predictability and nonstationarity of IDF curves. Risk management methods are examined to develop best practices for translating the characterization of irreducible uncertainty to guidelines for infrastructural decisions and resource allocations.