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This web page provides information on the design, status, and output of the International CLIVAR C20C+ Detection and Attribution Project. This is an international project aiming to produce a large pool of output from climate models and impact models for use in improving our understanding of extreme weather in the context of past and current climate change. It is a subproject of the World Climate Research Programme's (WCRP) Climate Variability Programme's (CLIVAR) Climate of the 20th Century Plus Project (C20C+).

• Summary •
Current climate model-based products are not optimised for research on extreme weather in the context of long-term climate change. The C20C+ Detection and Attribution Project is intended to fill this gap, by providing large samples of simulation data from climate models run at relatively high spatial resolution.
Models are run under two families of scenarios:
All-Hist: under the time-varying boundary conditions observed during the past few decades
Nat-Hist: same as All-Hist but with the anthropogenic contribution to the boundary conditions removed

For contributors
This project follows specific protocols for its experimental design. The Experiment page provides documentation on requested model setup, simulation characteristics, and output variables. It also provides links to surface (ocean temperatures and sea ice concentrations) boundary conditions for the Nat-Hist experiment family.
For researchers
Output from the simulations is available on the Earth System Grid Federation under project label "c20c", or via html. No registration is required. Details on available models, simulations, and climate variables are provided in the Data page.


  • 2017/07/20: ERRATUM: The last several years of LBNL/CAM5-1-2-025degree All-Hist/est1/v1-0 and Nat-Hist/CMIP5-est1/v1-0 had problems correctly using an input file. Please see C20CPlus-DA_publishing_status_LBNL_CAM5-1-2-025degree.ods or C20CPlus-DA_publishing_status_LBNL_CAM5-1-2-025degree.xls for details.
  • 2017/06/06: ERRATUM: ETH/CAM4-2degree Plus15-Future/CMIP5-MMM-est1/v1-0 and Plus20-Future/CMIP5-MMM-est1/v1-0 used an unintended value for the CO2 concentration. A replacement v2-0 will be available soon.
  • 2017/04/26: ERRATUM: LBNL/CAM5.1-1degree and LBNL/CAM5.1-0.25degree hurs was exactly 100 times too large for many files. Either divide by 100 when necessary (it is obvious) or download the corrected files.
  • 2016/10/12: LBNL will be hosting the 2nd C20C+ D&A Hackathon, 5-9 December 2016.
  • 2016/03/21: UCT-CSAG/HadAM3P-N96 All-Hist/est1/v2 and Nat-Hist/CMIP5-est1/v2 has been added to the data portal.
  • 2016/03/21: MOHC/HadGEM3-A-N216 has been added to the data portal.
  • 2016/03/10: The MIROC/MIROC5/All-Hist/est1/v2-0 simulations have been extended through 2015/10, and the MIROC/MIROC5/Nat-Hist/CMIP5-est/v1-0 simulations have been extended through 2014/12.
  • 2016/03/10: There was an error in the greenhouse gas setting for year 2013 of the MIROC/MIROC5/All-Hist/est1/v1-0 simulations. This has been corrected, and all MIROC/MIROC5/All-Hist/est1/v1-0 simulations have now been replaced with MIROC/MIROC5/All-Hist/est1/v2-0.
  • 2016/03/10: LBNL/CAM5-1-1degree/Nat-Hist/IPSL-CM5A-LR-est1/v2-0 has been added to the data portal.
  • 2015/10/14: ARCCSS/ACCESS1-3/All-Hist/est1/v1-0 has been added to the data portal.
  • 2015/07/03: Data from All-Hist/est1 and Nat-Hist/CMIP5-est1 simulations of CAM5.1-1degree and MIROC5 are now available on the data portal.

Maintained by: dstone@lbl.gov
Last updated: 20 July 2017

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