Global Improvement of Tropical Cyclone Representation Enhances Hindcasts of Extreme Sea Levels Over 68 Years

Abstract The underrepresentation of tropical cyclones (TCs) in state‐of‐the‐art atmospheric reanalyses such as ERA5 is well known, yet their impact on global hindcasts of extreme sea levels remains largely unaddressed. We show that weak TC signals in ERA5 cause severe underestimation, and in some cases near omission, of TC‐induced storm surges. To address this limitation, we leverage recent advances in TC observations and parametric modeling to improve TC representation in ERA5 surface winds and pressure fields, producing a 68‐year global sea level hindcast. The hindcast shows consistent improvements in TC‐induced surges of ∼25% globally, with improvements also extending to areas north of 44°N. The largest gains (∼40%) occur around Australia, where individual surge underestimation is reduced by up to 1.6 m. These improvements translate into more reliable return period estimates at tide gauges and substantial changes in estimated return periods across TC‐prone regions, with important implications for coastal flood risk assessment.