Fig. 6. Verification of an ensemble forecast with the probabilistic forecast error based on ensemble data with and without compression.
a, The 25-member uncompressed ensemble forecast (lines) of surface temperature in London, UK from 24 September 2020 up to 15 days ahead. b, Same as for a but the data are compressed in 4D space–time with Zfp, preserving 99% of real information. c, Same as for b but only preserving 93% of real information. d, Probabilistic forecast error (CRPS) for various levels of preserved information in the compression. The global mean CRPS has been calculated from 1,800 × 901 grid points.