Grey Swan Tropical Cyclones Simulated in Kilometer-Scale Earth System Models

In this presentation, recent simulations completed using both the Community Earth System Model (CESM) and the Energy Exascale Earth System Model (E3SM) at km-scale grid spacings are demonstrated. While there is a great deal of ongoing effort to support these model configurations for global model assessments in the coming decades, it is shown that actionable climate science is permitted with present computing architectures through the use of variable-resolution meshes and short-term "storylines."

Here, a technique for game planning "gray swan" tropical cyclones -- storms that are historically unrealized but physically plausible in current and future climates -- is described. When simulated with 3km CESM and E3SM, hurricanes strikingly resemble observed storms. While previous work has shown storm-total precipitation can be credibly captured by 25km climate models, hourly rain rates, commonly used by stakeholders for hazard planning, are more faithfully represented by km-scale models when compared to NEXRAD data. We also provide examples such as coupling simulated TC wind fields to outage prediction models to expose electric grid vulnerability, thereby opening opportunities to inform other sectors regarding TC risk in a physically consistent manner.