In this study, we perform an evaluation of PRIMAVERA high-resolution (25-50 km) Global Climate Models (GCMs) relative to CORDEX Regional Climate Models (RCMs) over Europe (12-50 km resolutions). It is the first time such assessment is performed for regional climate information using ensembles of GCMs and RCMs at similar horizontal resolutions. We perform this exercise for the distribution of daily precipitation contributions to rainfall bins over Europe 25 under current climate conditions. Both ensembles are evaluated against high quality national gridded observations in terms of resolution and station density. We show that PRIMAVERA GCMs simulate very similar distribution to CORDEX RCMs that CMIP5 cannot because of their coarse resolutions. PRIMAVERA and CORDEX ensembles generally show similar strengths and weaknesses. They are of good quality in summer and autumn in most European regions, but tend to overestimate precipitation in winter and spring. PRIMAVERA show improvements in the latter bias by reducing mid-rain 30 rate biases in Central and Eastern Europe. Moreover, CORDEX simulate less light rainfall than PRIMAVERA in most regions and seasons, which improves this common GCM bias. Finally, PRIMAVERA simulate less heavy precipitation than CORDEX in most regions and seasons, especially in summer. PRIMAVERA appear to be closer to observations. However, when we apply an averaged precipitation undercatch error of 20%, CORDEX become closer to these synthetic datasets.Considering 50 km resolution GCM or RCM datasets over Europe results in large benefits compared to CMIP5 models for 35 impact studies at the regional scale. The effect of increasing resolution from 50 km to 12 km in CORDEX simulations is, in comparison, small in most regions and seasons outside mountainous regions (due to the importance of orography) and coastal regions (mostly depending on the resolution of the land-sea contrast). Now that GCMs are able to reach the level of information provided by CORDEX RCMs run at similar resolutions, there is an opportunity to better coordinate GCM and RCM simulations for future model intercomparison projects.
1 IntroductionClimate models are essential tools to provide information on the evolution of climate quantities, their variability and interactions with various components of the Earth System. There have been two main streams of development in the climate modelling community: Global Climate Models (GCMs) and Regional Climate Models (RCMs). GCMs are complex models that account for interactions at the global scale between various components of the Earth System (e.g. atmosphere, ocean, sea 45 ice, vegetation). They are designed to balance model resolution, physics complexity and computational requirements, and are therefore commonly run at coarse spatial resolution. RCMs are complex models that dynamically downscale GCM results to obtain fine climate information at the regional scale. The main advantages of the dynamical downscaling approach are that: 1) RCMs are computationally cheaper and use a higher horizo...