Convection Resolving Climate Simulations

The aim of application of Regional Climate Models (RCMs) is to provide reliable informaion about climate and climate change on regional to local scales. The need for climate change results on convection resolving scale is increasing. RCMs based on non-hydrostatic models of the atmosphere can simulate the climate on grid scales down to 1 km, at which convective processes are partly to fully resolved. Due to limited computational resources the grid resolution and simulation domain vary substantially in Convection Resolving Climate Simulations (CRCS). The effective model resolution of the simulations is significantly smaller than the grid size, parameters describing the land scape have limited quality and/or resolution, and there is still a need for parameterisation of unresolved processes. This makes the set-up and the fidelity of the models dependent on the simulated region and domain of application. The added value, compared to coarser scale climate simulations, has only partly been demonstrated. The relevance of several processes for climate variability on local scales is unknown. High resolution observations are available for very few quantities only and not everywhere. The quality of simulated climate variability on regional to local scales is thus partly unknown and/or requires further improvement. Also, the quality of results is partly insufficient for usage in climate impact studies and makes a bias correction necessary. Hence, there is a need for coordinated research and development efforts: (i) on the development of generic km-scale climate model set-ups for long climate simulations, including specific parameterisations of regional and local effects (with relevance, e.g., for hydrology, renewable energy, agriculture, etc.); (ii) for further evaluation data and evaluation methods appropriate for CRCS simulations; (iii) for a be?er understanding of processes, mechanisms and variability of regional to local climate; (iv) to reduce model structural deficiencies, and to support model development. The working group is a pla`orm for discussion and collaboration on these aspects. The WG collaborates with other WGs in the CLM-Community and with national and international initiatives on convection resolving modelling.