B32. US precipitation extremes in E3SM

Title

Evaluation of precipitation extremes over the United States in E3SM compared to observations and CMIP6 simulations

Authors

Akinsanola AA (University of Georgia), Kooperman GJ (University of Georgia), Pendergrass AG (NCAR), Hannah WM (LLNL), and Reed KA (Stony Brook University)

Abstract

Realistically representing the present-day characteristics of extreme precipitation has been challenging for both gridded observations and Earth system model (ESM) simulations. In this project, we use a range of gridded observation datasets to assess simulations from Coupled Model Intercomparison Project Phase 6 (CMIP6) and Energy Exascale Earth System Model (E3SM) – including low-resolution, high-resolution, and super-parameterized versions. We evaluate precipitation over the United States with a comprehensive set of extreme precipitation indices and storm-specific statistics, including an assessment of magnitude, intensity, timing, and spatial structure across observations and ESMs. In addition to conventional ESMs, we assess the potential for high-resolution and super-parameterization, also known as a multi-scale modelling framework, implemented in E3SM, to improve key aspects of simulated precipitation compared to the standard version. Our preliminary results highlight common biases in CMIP6 ESMs and differences compared with E3SM, which are critical for understanding reliability of future projections of extreme precipitation.