The EC-Earth3 Earth system model for the Coupled Model Intercomparison Project 6

TLDR

The EC‑Earth community’s broad interests are reflected in the variety of possible configurations and sub‑models. The paper documents the EC‑Earth3 Earth system model for CMIP6, outlining its flexible coupling framework, major configurations, and physical performance over the historical period. It describes a methodology that ensures simulations are comparable across different high‑performance computing systems. EC‑Earth3’s key performance metrics show physical behavior and biases within the range of recent CMIP models, and its improved physical and dynamic features, new ESM components, and community tools represent a clear step forward over CMIP5, confirming its suitability for CMIP6 and beyond.

Abstract

The Earth system model EC-Earth3 for contributions to CMIP6 is documented here, with its flexible coupling framework, major model configurations, a methodology for ensuring the simulations are comparable across different high-performance computing (HPC) systems, and with the physical performance of base configurations over the historical period. The variety of possible configurations and sub-models reflects the broad interests in the EC-Earth community. EC-Earth3 key performance metrics demonstrate physical behavior and biases well within the frame known from recent CMIP models. With improved physical and dynamic features, new Earth system model (ESM) components, community tools, and largely improved physical performance compared to the CMIP5 version, EC-Earth3 represents a clear step forward for the only European community ESM. We demonstrate here that EC-Earth3 is suited for a range of tasks in CMIP6 and beyond.