Introduction

EC-Earth 4 is the next generation climate model developed by the EC-Earth consortium. This tutorial explains how to get and prepare the model source code, build the model, and how to run simple technical tests.

It is important to realise that EC-Earth 4 is still at an experimental stage, and so is this tutorial. The model code, as well as the build and run-time environment will frequently change. Features will be missing and platforms may not yet be supported. An attempt is made to keep this tutorial up-to-date, which means that details will change often and without prior notice. This includes in particular URLs to repositories and references to branches, steps to build or run the model, and supported features. It is therefore advised to double check the latest on-line version of the tutorial in case of problems.

The experimental state of development also implies that some of the steps are more complicated than they ought to be. Whenever this is the case, the tutorial mentions this and improvements can be expected.

The sources for this tutorial (not the model code!) are hosted at Github and automatically published to Read the Docs on every change. If there are problems with the tutorial as such, please open an issue in the Github project or consider contributing to the tutorial with a pull request.

However, some information that complements the tutorial is not openly available, due to licensing issues (e.g. access to initial state data). This type of information is therefore kept separately at the EC-Earth Development Portal, on a Wiki page (account required). However, as much information as possible is kept open in this tutorial.

This tutorial is based on the trunk version of EC-Earth 4, which, at the moment, includes OpenIFS 43r3v1 and NEMO 4.0.1. The ScriptEngine software is used to handle the build and runtime environment scripts and the OCP-Tool for automatic creation of the OASIS coupler set-up (see the Preparations section for details). The tutorial covers the AMIP (atmosphere-only) and GCM (atmosphere-ocean) configurations of EC-Earth 4.

Note

It is possible to prepare Makefiles, configurations and run scripts manually, thus building and running EC-Earth 4 without using ScriptEngine. However, this is not covered in this tutorial.