10 December 2019

The DOE E3SM Coupled Model Version 1: Description and Results at High Resolution

Overview of the High-Resolution Coupled E3SM Model.

Science

This study documents the first coupled high-resolution simulation of the E3SMv1 model. This simulation is generally superior to results from the low-resolution configuration of E3SMv1 and compares favorably to models in the CMIP5 ensemble. Surprisingly, changing resolution had little effect on model climate or aerosol sensitivity.

 

Impact

Finer resolution allows this simulation to explicitly resolve hurricanes, ocean eddies, and other climatologically-important processes that are handled by uncertain parameterizations at typical resolutions. Such simulations provide more credible predictions of future change and better-localized information about climate impacts. DOE has targeted high resolution as an area where it can shine due to its focus on high-performance computing.

Summary

The Energy Exascale Earth System Model (E3SM) is a relatively new fully-coupled Earth system and climate model used in major international model simulation projects and mission-defined efforts for the US Department of Energy. This paper describes the first simulation of the model in its high-resolution configuration. This higher-resolution version is able to capture the most energetic motions in the ocean, which are poorly represented in standard resolution coupled climate models, as well as the largest of storms in the atmosphere. Evaluation of this simulation confirms the benefits of high resolution found by other models with a few notable exceptions. These discrepancies with other studies are interesting because they provide a richer understanding of how and why resolution affects model bias. Another key finding is that climate and aerosol sensitivity in E3SM is unaffected by resolution change. This study also confirms the benefits of increased resolution for studying fine-scale features such as hurricanes and orographic precipitation. Finally, the high-resolution version of E3SM is shown to compare favorably to its low-resolution counterpart and to the models participating in Phase 5 of the Coupled Model Intercomparison Project.

Contact
Peter Caldwell
Lawrence Livermore National Laboratory
Publications
Caldwell, PM, A Mametjanov, Q Tang, L Van Roekel, J Golaz, W Lin, D Bader, et al.  2019.  "The DOE E3SM Coupled Model Version 1: Description and Results at High Resolution."  Journal of Advances in the Modeling of Earth Systems.  https://doi.org/10.1029/2019MS001870.