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the impact of e_we and e_sn on simulation

This post was from a previous version of the WRF&MPAS-A Support Forum. New replies have been disabled and if you have follow up questions related to this post, then please start a new thread from the forum home page.


Dear Office,

I wonder whether the grid number will influence the WRF simulation result:
time_step = 30,
max_dom = 1,
e_we = 100,
e_sn = 100,
dx = 4500,
dy = 4500,
parent_grid_ratio = 1,
parent_time_step_ratio = 1,

time_step = 3,
max_dom = 3,
e_we = 18, 22, 22,
e_sn = 18, 22, 22,
dx = 13500, 4500, 1500,
dy = 13500, 4500, 1500,
parent_grid_ratio = 1, 3, 3,
parent_time_step_ratio = 1, 3, 3,
See the two cases above, one is a single model domain, another is a nested model runs. If I compare the simulation results of 4500m resolution (domain 1 = 4500m) and 1500m resolution (domain 2 = 4500m), they should be same or different?

The attached files are my simulation results, you may refer to them.

Best regards,


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Dear Colleagues,

If anyone could provide some suggestions about my question above? Your help will be highly appreciated.

Dear Colleagues,

Anyone can help with this issue? Looking forward to hearing from you soon.

Best wishes,
Hi Stella,
Again, I apologize for the delay in response. As this question was posted under the same forum category as your other question, the same issue occurred.

We would expect the result to differ in these two cases, because in the nested simulation, domain 1 is receiving initial and boundary conditions from the input/first-guess data, and then updating the boundary and initial conditions for domain 2, based on domain 1. Whereas if you only have the single domain case, there is no update to a nested domain.
Dear Colleague,

Thank you for your answer. So, did you mean that the two cases with same resolution (4500m) should have different simulation results?
single model domain: domain1=4500m
nested model runs: domain2=4500m (domain1=1500m)

By the way, I wonder whether the grid number (e_we and e_sn) will influence the WRF simulation result?

Best regards,
Yes, that is what I meant. The difference will occur because of the fact that domain 2 is influenced by domain 1. And yes, the size of the domain (e_we and e_sn) will also cause slightly different results because the boundary conditions will be located in a different place.