HighResMIP versions of EC-Earth: EC-Earth3P and EC-Earth3P-HR – description, model computational performance and basic validation

A new global high-resolution coupled climate model, EC-Earth3P-HR has been developed by the EC-Earth consortium, with a resolution of approximately 40 km for the atmosphere and 0.25∘ for the ocean, alongside with a standard-resolution version of the model, EC-Earth3P (80 km atmosphere, 1.0∘ ocean). The model forcing and simulations follow the High Resolution Model Intercomparison Project (HighResMIP) protocol. According to this protocol, all simulations are made with both high and standard resolutions. The model has been optimized with respect to scalability, performance, data storage and post-processing. In accordance with the HighResMIP protocol, no specific tuning for the high-resolution version has been applied. Increasing horizontal resolution does not result in a general reduction of biases and overall improvement of the variability, and deteriorating impacts can be detected for specific regions and phenomena such as some Euro-Atlantic weather regimes, whereas others such as the El Niño–Southern Oscillation show a clear improvement in their spatial structure. The omission of specific tuning might be responsible for this. The shortness of the spin-up, as prescribed by the HighResMIP protocol, prevented the model from reaching equilibrium. The trend in the control and historical simulations, however, appeared to be similar, resulting in a warming trend, obtained by subtracting the control from the historical simulation, close to the observational one.
The EC-Earth simulations from SMHI were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC). The EC-EARTH simulations from BSC were performed on resources provided by ECMWF and the Partnership for Advanced Computing in Europe (PRACE; MareNostrum, Spain). Froila M. Palmeiro and Javier García-Serrano were partially supported by the Spanish GRAVITOCAST project (ERC2018-092835) and the “Ramón y Cajal” program (RYC-2016-21181), respectively, and MR was supported by “Beca de collaboració amb la Universitat de Barcelona” (2019.4.FFIS.1). The EC-Earth simulations from CNR were performed on resources provided by CINECA and ECMWF (special projects SPITDAVI and SPITMAVI). The EC-Earth simulations from KNMI were partly performed on resources provided by ECMWF (special project SPNLHAAR).
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Postprint (published version)