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New vigour involving statisticians to overcome ensemble fatigue

Abstract

Climate simulation data comprise a range of different phenomena with complex and interacting processes. Yet our understanding of the climate is incomplete despite the huge volumes of data, of which only a small fraction has been explored, and many questions remain, particularly those on the character and origin of uncertainties associated with model simulations and how further modelling efforts can improve understanding. Here, we question whether climate model information could be used more effectively and how so-called 'ensembles of opportunity' should be interpreted. Statisticians can contribute substantially to designing 'smarter' ensemble experiments, improving the distillation of information from ensembles, and helping interpret the relative merits of additional simulations. Future progress may be enhanced by increasing collaborations with statisticians.

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Figure 1: A schematic of the state probability space for a multi-model ensemble and the real world represented by a multi-dimensional probability density function.
Figure 2: Uncertainty of a statistical downscaling of 2050 sea-level rise projections relative to 1999 in Bergen, Norway.
Figure 3

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Acknowledgements

We thank E. U. Reed for his help with designing Fig. 3, and J. Rougier for providing constructive feedback on a previous version of the manuscript. J.S. is supported through the Norwegian Research Council projects ClimateXL (grant 243953) and TWEX (grant 255037). This work has been supported by the Statistical Analysis of Climate Projections project (eSACP; NordForsk grant number 74456), the COWI Foundation, the C-ICE Project (the Norwegian Research Council, project number 248803) and EU MCSA grant 707262 – LAWINE. The National Center for Atmospheric Research is sponsored by the National Science Foundation (NSF); M.R.T. is supported by the NSF's Decadal and Regional Climate Prediction using Earth System Models (EaSM-3) grants AGS-1419563, AGS-1419558 and AGS-1419504; T.L.T. is supported by the Norwegian Research Council through grant 243814.

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R.B., J.S. and T.L.T. conceived the original idea for the paper, wrote the text and generated Figs 1 and 3 and the figure in Box 1. T.L.T., P.G. and M.D. made Fig. 2. All authors contributed to discussions and writing of the text.

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Correspondence to Rasmus Benestad.

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Benestad, R., Sillmann, J., Thorarinsdottir, T. et al. New vigour involving statisticians to overcome ensemble fatigue. Nature Clim Change 7, 697–703 (2017). https://doi.org/10.1038/nclimate3393

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