Physics-based Risk Assessment of Compound Flooding from Tropical and
Extratropical Cyclones in a Warming Climate
Abstract
In recent years, efforts to assess the evolving risks of coastal
compound surge and rainfall-driven flooding from tropical cyclones (TCs)
and extratropical cyclones (ETCs) in a warming climate have intensified.
While substantial progress has been made, the persistent challenge lies
in obtaining actionable insights into the changing magnitude and
spatially-varying flood risks in coastal areas. We employ a
physics-based numerical hydrodynamic framework to simulate compound
flooding from TCs and ETCs in both current and future warming climate
conditions, focusing on the western side of Buzzard Bay in
Massachusetts. Our approach leverages hydrodynamic models driven by
extensive sets of synthetic TCs downscaled from CMIP6 climate models and
dynamically downscaled ETC events using the WRF model forced by CMIP5
simulations. Through this methodology, we quantify the extent to which
climate change can potentially reshape the risk landscape of compound
flooding in the study area. Our findings reveal a significant increase
in TC-induced compound flooding risk due to evolving climatology and sea
level rise (SLR). Additionally, there is a heightened magnitude of
compound flooding from ETCs, in coastal regions, due to SLR. Inland
areas exhibit a decline in rainfall-driven flooding from high-frequency
ETC events toward the end of the century compared to the current
climate. Our methodology is transferable to other vulnerable coastal
regions, serving as a valuable decision-making tool for adaptive
measures in densely populated areas. It equips decision-makers and
stakeholders with the means to effectively mitigate the destructive
impacts of compound flooding arising from both current and future TCs
and ETCs.