Multi-Model Large Ensemble Archive (MMLEA)

As part of its activities, the US CLIVAR Working Group on Large Ensembles has produced a centralized data archive of initial-condition Large Ensembles conducted with currently up to 7 CMIP5-class climate models. This archive contains gridded fields of key variables at both daily and monthly resolution, and is publicly accessible via the NCAR Research Data Archive or via NCAR’s casper or derecho systems at /glade/campaign/collections/rda/data/d651014/.  (Note that the complete MPI-ESM Large Ensemble is available here.)

The table below provides a summary of the salient characteristics of the models and simulations contained within the archive. Further discussion of the utility and applications of the archive is given in the reference below. Please direct questions about this archive to Dr. Flavio Lehner [ flehner@ucar.edu ] or Dr. Clara Deser [ cdeser@ucar.edu ].

We kindly ask that you acknowledge the US CLIVAR Working Group on Large Ensembles and reference Deser et al. (2020) when presenting results based on the Multi-Model Large Ensemble Archive in either oral or written form.

Deser, C., F. Lehner, K. B. Rodgers, T. Ault, T. L. Delworth, P. N. DiNezio, A. Fiore, C. Frankignoul, J. C. Fyfe, D. E. Horton, J. E. Kay, R. Knutti, N. S. Lovenduski, J. Marotzke, K. A. McKinnon, S. Minobe, J. Randerson, J. A. Screen, I. R. Simpson and M. Ting, 2020: Insights from Earth system model initial-condition large ensembles and future prospects. Nature Climate Change, doi: 10.1038/s41558-020-0731-2. [Article][Read-only]

The archive also includes an “Observational Large Ensemble” (Obs-LE) for temperature (land only), precipitation (land only), and sea level pressure (global), which can be used to sample alternative but non-observed historical climate trajectories. These data are based on a statistical model and described in McKinnon and Deser (2018). Further details and the code to reproduce the Obs-LE can be found on github. Please direct questions about the Obs-LE to Prof. Karen McKinnon [ kmckinnon@ucla.edu ].

Additional LE resources for historical and scenario simulations exist within CMIP6. These are listed below and are available from the standard CMIP server at ESGF. We focus on models that have at least 15 members in the historical period. This table was last updated in January 2024. If you know of public large ensemble resources not yet listed, get in touch with Dr. Flavio Lehner [ flehner@ucar.edu ].

Finally, modeling groups have started to produce multi-member ensembles for single-forcing simulations. Some follow the CMIP DAMIP protocol (with experiments such as 'hist-nat', 'hist-GHG', etc). Others use independent experimental setups, such as "everything-but-X" forcing, or idealized aerosol forcing scaling.