Time step size estimate

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xtian15

Member
Hi,
My question is about the time step size when running MPAS with full physics. I am aware that the time step sizes are often given the value of 6x of grid spacing in km. Under the "6x" scenarios, what should the value of "config_dynamics_split_steps" be? I am asking because when I tried to run a 3-60 variable resolution mesh, simulations with step sizes greater than 10s tend to explode, in which the "config_dynamics_split_steps=1". Thanks in advance for your help!
 
The default value for "config_dynamics_split_steps" is 3; did you have a specific reason for changing this parameter? It's probably worth trying a test run with the following parameters set to their default values:
Code: 
    config_time_integration_order = 2
    config_split_dynamics_transport = true
    config_number_of_sub_steps = 2
    config_dynamics_split_steps = 3
 
Thanks Michael!
I wanted to change the config_dynamics_split_steps into 1 hoping to save a bit of running time, as 3 is to integrate the dynamics 3 times. But config_dynamics_split_steps=1 makes the system quite unstable so I'll just change it back to the default 3. Thanks again for confirming!
 
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