Abstract. 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.