标题：Development and prospects of the regional MiKlip decadal prediction system over Europe: predictive skill, added value of regionalization, and ensemble size dependency
摘要：The current state of development and the prospects of the regional MiKlip decadal prediction systemfor Europe are analysed. The MiKlip regional system consists of two 10-member hindcastensembles computed with the global coupled model MPI-ESM-LR downscaled for the Europeanregion with COSMO-CLM to a horizontal resolution of 0.22∘ (∼25km).Prediction skills are computed for temperature, precipitation, and wind speed using E-OBSand an ERA-Interim-driven COSMO-CLM simulation as verification datasets. Focus is givento the eight European PRUDENCE regions and to lead years 1–5 after initialization.Evidence of the general potential for regional decadal predictability for all threevariables is provided. For example, the initialized hindcasts outperform theuninitialized historical runs for some key regions in Europe, particularly in southernEurope. However, forecast skill is not detected in all cases, but it depends on thevariable, the region, and the hindcast generation. A comparison of the downscaledhindcasts with the global MPI-ESM-LR runs reveals that the MiKlip prediction system maydistinctly benefit from regionalization, in particular for parts of southern Europe andfor Scandinavia. The forecast accuracy of the MiKlip ensemble is systematically enhancedwhen the ensemble size is increased stepwise, and 10 members is found to be suitable fordecadal predictions. This result is valid for all variables and European regions in boththe global and regional MiKlip ensemble. The present results are encouraging for thedevelopment of a regional decadal prediction system.
