  We systematically validate the static local mesh refinement capabilities of a
recently proposed IMEX-DG scheme implemented in the framework of the deal.II
library. Non-conforming meshes are employed in atmospheric flow simulations to
increase the resolution around complex orography. A number of numerical
experiments based on classical benchmarks with idealized as well as real
orography profiles demonstrate that simulations with the refined mesh are
stable for long lead times and no spurious effects arise at the interfaces of
mesh regions with different resolutions. Moreover, correct values of the
momentum flux are retrieved and the correct large-scale orographic response is
established. Hence, large-scale orography-driven flow features can be simulated
without loss of accuracy using a much lower total amount of degrees of freedom.
In a context of spatial resolutions approaching the hectometric scale in
numerical weather prediction models, these results support the use of locally
refined, non-conforming meshes as a reliable and effective tool to greatly
reduce the dependence of atmospheric models on orographic wave drag
parametrizations.
