With exascale computing becoming available in the next decade, global weather prediction at the kilometer scale will be enabled. Moreover, the climate community has already begun to contemplate a new generation of high-resolution climate models.

High-resolution model development is confronted with several challenges. Scalability of the models needs to be optimal, including all relevant components such as I/O which easily becomes a bottleneck; both runtime and I/O will dictate how fine a resolution can be chosen while still being able to run the model at production level; 1-30 years/day are anticipated for this purpose, depending on the questions to be addressed. Moreover, given various scalability experiments from prototypical runs and additional model data, estimating performance for new simulations can become challenging.

I present results achieved in the scope of the Centre of Excellence in Simulation of Weather and Climate in Europe (ESiWACE) for global high-resolution simulations. I show results from multi-week global 5km simulations, and I discuss current features and limits of the simulations. I further link the findings to a new intercomparison initiative DYAMOND for high-resolution predictions. Finally, I discuss performance prediction approaches for existing performance data.