Characterizing Inland Compound Flooding Events over North America
Abstract
Multiple hydrometeorological drivers can contribute to inland compound flooding with potentially severe societal or environmental impacts. Understanding regional variability in compound flood events and the uncertainties associated with climate change assessment are critical for future engineering design and planning. In this study, we characterize three main inland compound flooding events, i.e., two preconditioned events, rain-on-snow (ROS) and saturation excess flooding (SEF), and a temporally compounding event represented by a series of precipitation (SOP) in North America. The analyses are based on the 50-member CanRCM4 large ensemble simulations for 1986-2016 as the baseline, as well as three 31-year time frames corresponding to the warming levels of 2, 3, and 4℃ compared to the preindustrial levels (PI). The frequency of compound events is extracted based on absolute thresholds and quantile-based criteria for robust statistical analysis of compound events. Using the spread of the ensemble distribution, we then investigate how internal climatic dynamics affect inland compound floods. ROS events are more likely to occur along the eastern and western coastal regions than in the central parts. At higher warming levels, the chance of a ROS events happening in the mountain regions of Canada can increase, however, it is projected to decline on the western coast of the US, compared to the baseline period. The regions with a high occurrence probability for SEF events are mostly located at low latitudes and southern regions of the US. SOP mostly occurs in low-latitude regions, western and central arid parts of the US, and mountain regions of Canada. However, at higher warming levels, the SOP probability of occurrence is expected to rise in the tropical regions, while this probability in other regions would decrease. This study can lead to enhanced flood estimations by considering the suite of regional compound flood-generating factors within North America.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMNH41A..01F