Tropical Cyclone Weather Extremes and Flooding Impacts in a Global Climate Model Large Ensemble Partnered with a High-Resolution Hydrology Model
Increasing vulnerability to flooding hazards arises from amplifying weather extremes, sea level rise (SLR), and accelerating urban development. These dangers are stressed by tropical cyclones, which can produce damaging compound flooding from concurrent heavy rainfall, increased river flows, and storm surge. The extent of impacts due to tropical cyclones is further influenced by climate trends and coastal geography. Previous studies indicate that climate warming has resulted in tropical cyclones that can produce more rain, while SLR has exacerbated the damage potential of tropical cyclone-driven storm surge. As part of the Integrated Coastal Modeling (ICoM) project, this study links a global climate model, a high-resolution hydrology model, and an electrical power system model to examine impacts associated with Hurricane Irene (2011), a storm that caused severe compound flooding in the eastern U.S. We first investigate the ability of the DOE Energy Exascale Earth System Model (E3SM) version 2 to reproduce meteorological conditions associated with Hurricane Irene. E3SM is configured with a regionally refined horizontal grid mesh, and a large ensemble of simulations are conducted to better capture model uncertainty. We find that E3SM can simulate the properties of Hurricane Irene reasonably well at lead times of 48-60 hours. Flood mechanisms are intrinsically complex in this region due to its sharp hydroclimatic gradients from mountainous terrain to coastal plains. To explore whether the comparatively coarse-resolution E3SM simulations can capture the heterogeneity in regional flood patterns and inform regional flood risk assessment, E3SM meteorological outputs are processed to drive a physics-based, high-resolution hydrology model (DHSVM) that represents runoff processes at a 150m spatial resolution. Uncertainties propagating from atmospheric conditions to river flooding are examined using the ensemble approach. We also use E3SM and DHSVM output to estimate the risk on the electrical power system caused by Hurricane Irene. This study highlights one aspect of ICoM’s cross-cutting activities that aim to partner climate and infrastructure scientists, hydrologists, and others to improve our modeling ability and predictive understanding of coastal processes in current and future climates.