Here are two configurations listed below: the differences between these two are domain-ratios: the regular one is designed with the domain-ratio of 3 containing 5 domains, while another is designed with a domain-ratio of 9 including3 domains.

My questions are: is the ratio of 3 among domain-resolutions necessary for WRF design or the ratio of 9 is also fine (where can I find the information talking about the ratio among domains)? Are there some differences in model results between these two options listed below?

Regular options:

max_dom = 5,

e_we = 222, 334, 667, 502, 301,

e_sn = 222, 334, 667, 502, 301,

dx = 27000, 9000, 3000, 1000, 333.3,

dy = 27000, 9000, 3000, 1000, 333.3,

grid_id = 1, 2, 3, 4, 5,

parent_id = 1, 1, 2, 3, 4,

Another options:

max_dom = 3,

e_we = 222, 667, 301,

e_sn = 222, 667, 301,

dx = 27000, 3000, 333.3,

dy = 27000, 3000, 333.3,

grid_id = 1, 2, 3,

parent_id = 1, 1, 2,

Thanks for your attention.

All the best!

Nannan