The material in this Project Pythia Cookbook is licensed for free and open consumption and reuse. All code is served under Apache 2.0, while all non-code content is licensed under Creative Commons BY 4.0 (CC BY 4.0). Effectively, this means you are free to share and adapt this material so long as you give appropriate credit to the Cookbook authors and the Project Pythia community.
The source code for the book is released on GitHub. A Zenodo DOI is issued on the first tagged release; until then, cite the repository by URL and commit.
Citing the data¶
The chapters read the AWS Open Data copy of the CESM2 Large Ensemble. NSF NCAR’s Data Citation section, which the UCAR Data Terms of Use bind users to, asks that both the dataset and the paper be cited:
Grover, M., & Banihirwe, A. (2021). NCAR CESM2 Large Ensemble Cloud-Optimized Dataset. NSF NCAR Computational and Information Systems Laboratory. doi:10.26024/y48t-q717
Rodgers, K. B. et al. (2021). Ubiquity of human-induced changes in climate variability. Earth System Dynamics 12, 1393–1411. doi:10.5194/esd-12-1393-2021
Access line (historical table, data/member_winters.csv): Community Earth System Model v2 Large Ensemble (CESM2 LENS) was accessed on 2026-10-20 from https://
Access line (SSP3-7.0 table, data/member_winters_ssp370.csv, from the ssp370 stores of the same dataset): Community Earth System Model v2 Large Ensemble (CESM2 LENS) was accessed on 2026-10-29 from https://
Results based on the CESM2 Large Ensemble acknowledge the CESM2 Large Ensemble Community Project and supercomputing resources provided by the IBS Center for Climate Physics in South Korea.