@article{002d6d508af142508f0305edbec8a197,
title = "Robust Evaluation of ENSO in Climate Models: How Many Ensemble Members Are Needed?",
abstract = "Large ensembles of model simulations require considerable resources, and thus defining an appropriate ensemble size for a particular application is an important experimental design criterion. We estimate the ensemble size (N) needed to assess a model{\textquoteright}s ability to capture observed El Ni{\~n}o-Southern Oscillation (ENSO) behavior by utilizing the recently developed International CLIVAR ENSO Metrics Package. Using the larger ensembles available from CMIP6 and the US CLIVAR Large Ensemble Working Group, we find that larger ensembles are needed to robustly capture baseline ENSO characteristics (N > 50) and physical processes (N > 50) than the background climatology (N ≥ 12) and remote ENSO teleconnections (N ≥ 6). While these results vary somewhat across metrics and models, our study quantifies how larger ensembles are required to robustly evaluate simulated ENSO behavior, thereby providing some guidance for the design of model ensembles.",
keywords = "CLIVAR ENSO metrics, CMIP6, ENSO, large ensemble, Monte-Carlo sampling, PCMDI metrics package (PMP)",
author = "Jiwoo Lee and Planton, \{Yann Y.\} and Gleckler, \{Peter J.\} and Sperber, \{Kenneth R.\} and Eric Guilyardi and Wittenberg, \{Andrew T.\} and McPhaden, \{Michael J.\} and Giuliana Pallotta",
note = "Funding Information: Work of LLNL‐affiliated authors was performed under the auspices of the U.S. Department of Energy (DOE) by Lawrence Livermore National Laboratory under Contract DE‐AC52‐07NA27344 via the Regional and Global Climate Modeling Program. The authors thank the CLIVAR Pacific Panel members and ENSO experts for a number of fruitful discussions. The authors acknowledge the World Climate Research Programme's Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modeling groups for producing and making available their model output, the Earth System Grid Federation (ESGF) for archiving the output and providing access, and the multiple funding agencies who support CMIP and ESGF. The U.S. Department of Energy's Program for Climate Model Diagnosis and Intercomparison (PCMDI) provides coordinating support and led development of software infrastructure for CMIP. The authors thank the US CLIVAR Working Group on Large Ensembles for making the Multi‐Model Large Ensemble Archive (MMLEA) publically available. The altimeter products were produced by Ssalto/Duacs and distributed by Aviso+, with support from Cnes. ERA‐Interim data are provided by ECMWF. The TropFlux data are produced under a collaboration between Laboratoire d{\textquoteright}Oc{\'e}anographie: Exp{\'e}rimentation et Approches Num{\'e}riques (LOCEAN) from Institut Pierre Simon Laplace (IPSL; Paris, France) and National Institute of Oceanography/CSIR (NIO; Goa, India), and supported by Institut de Recherche pour le D{\'e}veloppement (IRD; France). TropFlux relies on data provided by the ECMWF interim reanalysis (ERA‐Interim) and ISCCP projects. Support for the Twentieth Century Reanalysis Project version 3 data set is provided by the U.S. Department of Energy, Office of Science Biological and Environmental Research (BER), by the National Oceanic and Atmospheric Administration Climate Program Office, and by the NOAA Physical Sciences Laboratory. This is PMEL Contribution No. 5276. The authors acknowledge the support from the Agence Nationale de la Recherche ARISE project, under Grant ANR‐18‐CE01‐0012, and the Belmont project GOTHAM, under Grant ANR‐15‐JCLI‐0004‐01, the European Commission{\textquoteright}s H2020 Programme “Infrastructure for the European Network for Earth System Modelling Phase 3 (IS‐ENES3)” project under Grant Agreement 824084. Funding Information: Work of LLNL-affiliated authors was performed under the auspices of the U.S. Department of Energy (DOE) by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 via the Regional and Global Climate Modeling Program. The authors thank the CLIVAR Pacific Panel members and ENSO experts for a number of fruitful discussions. The authors acknowledge the World Climate Research Programme's Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modeling groups for producing and making available their model output, the Earth System Grid Federation (ESGF) for archiving the output and providing access, and the multiple funding agencies who support CMIP and ESGF. The U.S. Department of Energy's Program for Climate Model Diagnosis and Intercomparison (PCMDI) provides coordinating support and led development of software infrastructure for CMIP. The authors thank the US CLIVAR Working Group on Large Ensembles for making the Multi-Model Large Ensemble Archive (MMLEA) publically available. The altimeter products were produced by Ssalto/Duacs and distributed by Aviso+, with support from Cnes. ERA-Interim data are provided by ECMWF. The TropFlux data are produced under a collaboration between Laboratoire d?Oc?anographie: Exp?rimentation et Approches Num?riques (LOCEAN) from Institut Pierre Simon Laplace (IPSL; Paris, France) and National Institute of Oceanography/CSIR (NIO; Goa, India), and supported by Institut de Recherche pour le D?veloppement (IRD; France). TropFlux relies on data provided by the ECMWF interim reanalysis (ERA-Interim) and ISCCP projects. Support for the Twentieth Century Reanalysis Project version 3 data set is provided by the U.S. Department of Energy, Office of Science Biological and Environmental Research (BER), by the National Oceanic and Atmospheric Administration Climate Program Office, and by the NOAA Physical Sciences Laboratory. This is PMEL Contribution No. 5276. The authors acknowledge the support from the Agence Nationale de la Recherche ARISE project, under Grant ANR-18-CE01-0012, and the Belmont project GOTHAM, under Grant ANR-15-JCLI-0004-01, the European Commission?s H2020 Programme ?Infrastructure for the European Network for Earth System Modelling Phase 3 (IS-ENES3)? project under Grant Agreement 824084. Publisher Copyright: {\textcopyright} 2021. American Geophysical Union. All Rights Reserved.",
year = "2021",
month = oct,
day = "28",
doi = "10.1029/2021GL095041",
language = "English",
volume = "48",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "Wiley-Blackwell",
number = "20",
}
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