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EAMxx

A High-performance E3SM Atmosphere Model in C++

EAMxx was designed and built from the ground up employing modern C++ in order to embrace leading-edge software practices and enable "performance portability" 1 across various leadership-class supercomputers. The latter goal is achieved by using the Kokkos library. EAMxx is a "clean-start" model with almost no similarity to the E3SM atmosphere model used in versions 1-3. Currently only the km-scale explicit-convection version called SCREAM2 (the Simple Cloud-Resolving E3SM Atmosphere Model) is available, but a low-resolution version is in development.

Trail Map

Like the documentation for other component models, EAMxx documentation is divided into the following sections:

  • User Guide - info about running EAMxx and all options for modifying a simulation
  • Developer Guide - information needed to contribute to EAMxx development
  • Technical Guide - equations and numerical methods used in EAMxx

Put another way, the User Guide provides information about how to successfully run a model that includes EAMxx and how to customize runs without changing source code. The Developer Guide includes information about EAMxx software design that will assist those who wish to intelligently modify source code. Scientific and modeling details about the specific process implementations in the current model version are provided in the Technical Guide.

  1. Performance Portability: A software-design practice focused on providing the ability to run the same model on differing architectures (cpu, gpu, ...) without modifying the source code and, ideally, without sacrificing performance. ↩

  2. Note: Prior to EAMxx version 1, this project, software library, and atmosphere driver were generally referred to as SCREAM. However, at this point, we wish to make the distinction between EAMxx, the next-gen atmosphere driver and C++ software library, and SCREAM, the particular high-resolution configuration of EAMxx. ↩