Future intensity-duration-frequency curves of extreme precipitation in
the Midwest United States from convection-permitting modelling
Abstract
During the last four decades, global warming has intensified extreme
precipitation events in the Midwestern United States (defined here as
the region covering Illinois, Indiana, Ohio and Kentucky), leading to
increased risks to human life, property, and infrastructure. To enable
climate change adaptation and resilience across various economic and
social sectors in this region, updated information about future climate
changes, specifically at finer spatial scales, is essential. Leveraging
a new 150-year dynamical downscaling dataset at convection-permitting
resolution, this study introduces a framework to construct the projected
future intensity-duration-frequency (IDF) curves of heavy precipitation,
which are prominent tools for infrastructure design and water resources
management. This framework generates IDF curves at both sub-daily and
multi-day duration utilizing hourly in situ observations as well as
quantile-based statistical techniques in bias-correction and return
levels selection. The assumption of non-stationarity in the distribution
parameter fitting process is also implemented in this workflow. Compared
to historical IDF curves for 1980-2022, future projected IDF curves for
2058-2100 under Representative Concentration Pathway (RCP) 4.5 and RCP
8.5 scenarios indicate an average intensity increase of approximately
20% and 30%, respectively, across 74 stations and all four seasons of
interest. The frequency of future extreme precipitation events in the
Midwest region is also projected to double. Furthermore, current results
reveal spatial heterogeneity of future trends across stations owing to
the high-resolution input dataset.