I'm using OpenIFS 40r1 for some long integrations. I have been testing using a different model timestep but found that the amount of low cloud simulated by the model is sensitive to the timestep. I'm using the recommended timestep from the OpenIFS FAQ but have also tried much shorter stepslonger steps but then warnings about 'trajectories underground' appear in the log file.
Can you please advise on the correct timestep and why the low cloud changes?
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