EGU21-3476, updated on 03 Mar 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Recent developments on the Earth System Model Evaluation Tool

Bouwe Andela1, Fakhereh Alidoost1, Lukas Brunner8, Jaro Camphuijsen1, Bas Crezee8, Niels Drost1, Bettina Gier6,5, Birgit Hassler5, Peter Kalverla1, Axel Lauer5, Saskia Loosveldt-Tomas2, Ruth Lorenz8, Valeriu Predoi3, Mattia Righi5, Manuel Schlund5, Stef Smeets1, Javier Vegas-Regidor2, Jost Von Hardenberg7,9, Katja Weigel6,5, and Klaus Zimmermann4
Bouwe Andela et al.
  • 1Netherlands eScience Center, Netherlands (
  • 2Barcelona Supercomputing Centre, Barcelona, Spain
  • 3NCAS-CMS, University of Reading, Reading, United Kingdom
  • 4SMHI, Norrköping, Sweden
  • 5DLR, Munich, Germany
  • 6University of Bremen, Bremen, Germany
  • 7Politecnico di Torino, Torino, Italy
  • 8ETH, Zurich, Switzerland
  • 9ISAC-CNR, Torino, Italy

The Earth System Model Evaluation Tool (ESMValTool) is a free and open-source community diagnostic and performance metrics tool for the evaluation of Earth system models such as those participating in the Coupled Model Intercomparison Project (CMIP). Version 2 of the tool (Righi et al. 2020, features a brand new design composed of a core that finds and processes data according to a ‘recipe’ and an extensive collection of ready-to-use recipes and associated diagnostic codes for reproducing results from published papers. Development and discussion of the tool (mostly) takes place in public on and anyone with an interest in climate model evaluation is welcome to join there.


Since the initial release of version 2 in the summer of 2020, many improvements have been made to the tool. It is now more user friendly with extensive documentation available on and a step by step online tutorial. Regular releases, currently planned three times a year, ensure that recent contributions become available quickly while still ensuring a high level of quality control. The tool can be installed from conda, but portable docker and singularity containers are also available.


Recent new features include a more user-friendly command-line interface, citation information per figure including CMIP6 data citation using ES-DOC, more and faster preprocessor functions that require less memory, automatic corrections for a larger number of CMIP6 datasets, support for more observational and reanalysis datasets, and more recipes and diagnostics.


The tool is now also more reliable, with improved automated testing through more unit tests for the core, as well as a recipe testing service running at DKRZ for testing the scientific recipes and diagnostics that are bundled into the tool. The community maintaining and developing the tool is growing, making the project less dependent on individual contributors. There are now technical and scientific review teams that review new contributions for technical quality and scientific correctness and relevance respectively, two new principal investigators for generating a larger support base in the community, and a newly created user engagement team that is taking care of improving the overall user experience.

How to cite: Andela, B., Alidoost, F., Brunner, L., Camphuijsen, J., Crezee, B., Drost, N., Gier, B., Hassler, B., Kalverla, P., Lauer, A., Loosveldt-Tomas, S., Lorenz, R., Predoi, V., Righi, M., Schlund, M., Smeets, S., Vegas-Regidor, J., Von Hardenberg, J., Weigel, K., and Zimmermann, K.: Recent developments on the Earth System Model Evaluation Tool, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3476,, 2021.