The CanESM2 large ensembles are 50-member perturbed initial condition ensembles from 1950 to 2020, with all historical forcings (historical), solar and volcanic forcings only (historicalNat), anthropogenic aerosols only (historicalMisc, p4), and ozone only (historicalMisc, p6). The model, forcings, variable names and file formats all follow those used in the Coupled Model Intercomparison Project Phase 5 (CMIP5). Each of the five members of the existing CMIP5 historical ensemble had conditions perturbed in 1950 ten times to produce a new ensemble of fifty simulations starting in 1950, and a similar procedure was applied to the natural, aerosol and ozone-only ensembles. Simulations were run to 2005 using CMIP5 historical forcings and then to 2020 using RCP 8.5 forcings. The CanESM2 large ensembles were proposed by the Canadian Sea Ice and Snow Evolution Network (CanSISE) Climate Change and Atmospheric Research (CCAR) Network project, which also coordinated much of the initial analysis of the large ensembles.
Relevant publications:
Description of the large ensembles:
Kushner, P. J., L. R. Mudryk, W. Merryfield, J. T. Ambadan, A. Berg, A. Bichet, R. Brown, C. Derksen, S. J. Déry, A. Dirkson, G. Flato, C. G. Fletcher, J. C. Fyfe, N. Gillett, C. Haas, S. Howell, F. Laliberté, K. McCusker, M. Sigmond, R. Sospedra-Alfonso, N. F. Tandon, C. Thackeray, B. Tremblay, and F. W. Zwiers, 2018: Canadian snow and sea ice: assessment of snow, sea ice, and related climate processes in Canada’s Earth system model and climate-prediction system. The Cryosphere, 12, 1137–1156, doi:10.5194/tc-12-1137-2018.
Kirchmeier-Young, M.C., F.W. Zwiers, and N.P. Gillett, 2017: Attribution of Extreme Events in Arctic Sea Ice Extent. J. Climate, 30, 553–571, https://doi.org/10.1175/JCLI-D-16-0412.1
Examples of applications of the large ensembles:
Kirchmeier-Young, M.C., F.W. Zwiers, N.P. Gillett and A.J. Cannon, 2017: Attributing extreme fire risk in Western Canada to human emissions, Climatic Change, 1-15, https://doi.org/10.1007/s10584-017-2030-0
Gagné, M.-È., J. C. Fyfe, N. P. Gillett, I. V. Polyakov, and G. M. Flato, 2017: Aerosol-driven increase in Arctic sea ice over the middle of the twentieth century, Geophys. Res. Lett., 44, 7338–7346, https://doi.org/10.1002/2016GL071941
Gagné, M.-È., M. C. Kirchmeier-Young, N. P. Gillett, and J. C. Fyfe, 2017: Arctic sea ice response to the eruptions of Agung, El Chichón, and Pinatubo, J. Geophys. Res. Atmos., 122, https://doi.org/10.1002/2017JD027038
Fyfe, J.C. , C. Derksen, L. Mudryk, G.M. Flato, B.D. Santer, N.C. Swart, N.P. Molotch, X. Zhang, H. Wan, V.K. Arora, J. Scinocca, 2017: Large near-term projected snowpack loss over the western United States, Nature Comm., 8:14996, https://doi.org/10.1038/ncomms14996