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1. Try to get a namelist as starting point:
   1. Check if somebody has already performed a simulation on this domain or a similar domain. If this is the case try to get namelist from the namelist tool or the person directly and use this namelist as starting point.
   2. If there is no simulation for your target domain, or if you can't get a namelist, check if a simulation for a domain in a similar climate zone (mid-latitudes, tropics, maritime, continental, flat, mountainous) has been done and use this namelist as starting point.
2. Take the recommended COSMO-CLM version and incorporate the domain specific changes from the namelist of step 1.
3. Perform an ERA-Interim simulation (ideally for 30 years but at least for 10 years) and analyze if the results are reasonable.
4. Test as many different setups as possible to find the best possible setup for your domain. For this step, the method proposed by Bellprat et at. can be used (Bellprat. O, S. Kotlarski, D. Lüthi, C. Schär (2012): Objective calibration of regional climate models. Journal of Geophysical Research, 117, D23115, DOI: 10.1029/2012JD018262. https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2012JD018262).
5. Perform tests with similar setup but different time steps to avoid wrong results as consequence of the time step problem (Qne time step can give very different results for e.g pressure, precipitation compared to all other timesteps. This time step should not be used climate simulations. For the EURO-CORDEX domain the recommended configuration gives wrong results with a time step of 120 seconds. Since the problem is very likely resolution and domain dependent, no general recommendation can be given.)
6. Choose the best setup for your domain according to your tests.
7. Send your namelist to Andreas Will (andreas.will[at]b-tu.de) for inclusion in the namelist tool.
8. Write a short report on your tests and the outcome and send it to the coordinator of the working group WG EVAL.

WG SUPTECH strongly recommends to use ONLY the recommended COSMO-CLM configuration for simulations in the EURO-CORDEX domain (visit the namelist-tool for detailed settingsinformation about the setup).

For every other configuration, even slightly changed configuration if it is only slightly different to the recommended setup (e.g., domain size, resolution, atmosphere height, time step, tuning parameters, etc.), tests are necessary whether the new configuration encounters this problem; e.g., the recommended configuration with a time step of 120s leads to the reported unrealistic behaviour of the simulation.to verify the reliability of the new configuration.)

In these tests the tested configuration should be run with at least 2 different time steps and the results should be compared w.r.t. the RMSE of the PSML. If they differ significantly, the results should be analysed against observations or, if a simulation optained by using a third time step gives comparable results to one of two other simulations, then as far as it is known up-to-now, the time steps with comparable results are assumed to be more realistic. Please consider, that the time steps of-course need to fulfil the CFL criterion.

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