Advancing compound modelling of tropical cyclone wind, surge and rain impacts – now and in a changing climate

Intense precipitation from tropical cyclones (TCs), typically accompanied by wind-driven storm surges and highly destructive winds, constitutes a significant threat for compound flooding and wind-driven impacts in many coastal regions worldwide. However, most present TC risk assessment methods only consider wind as the driving hazard and thus underestimate impacts emerging from compounding TC sub-hazards. Further, it is crucial to understand how this risk will shift and intensify in a warming climate. We thus present a coupled, physics-based modeling approach for the coastal area of Metropolitan Manila (PHL) to explicitly represent TC rainfall-induced freshwater flood, TC wind-driven storm surges, and direct impacts from TC wind for present and future climate. We use a large set of synthetic TCs generated from historical climate data (1985-2014) and from the late 21st century (2071-2100) SSP585 warming scenario to simulate TC wind fields and rainfall intensity data. Our modelling chain includes a hydrodynamical component to convert TC precipitation to freshwater flood and model wind-driven storm surges. We evaluate the compound socio-economic impacts from the TC sub-hazards using a state-of-the-art, open-source probabilistic damage model (CLIMADA). Ultimately, our advances in TC impact modelling can be applied in vulnerable coastal regions worldwide, enabling better-informed adaptation decisions and mitigation strategies.