Climate configuration of the model ALADIN at CHMI

For operational weather forecast at CHMI we use the ALARO configuration of the numerical system ALADIN with horizontal resolution 2.3km. It is so-called convection permitting model. The goal of presented work was to evaluate potential of operational ALARO configuration used for Central Europe, and apply it with minimal changes for baseline regional climate simulations realized within the PERUN project. Tests following the so-called big brother experimental protocol were performed, demonstrating ability of the regional model to add short scales missing in the boundary conditions from driving model ESM2-1 in the region of interest over Czech territory, even though the resolution of driving model is more than order of magnitude coarser. Further it was verified that in the computational domain synoptic scales are sufficiently controlled by lateral boundary conditions. Thanks to this, consistency with driving global scenario is ensured even without use of spectral nudging. Such approach enables to fully profit from high resolution of the regional model, when internal variability generated by convective or orographic circulations is not artificially restricted.