i_parent_start and j_parent_start
As a rough approximation, keep about 1/3 of the coarse-grid domain surrounding each side of the nest.
Your nest domain dimensions will be (ending index - starting index)*3+1
e_we and e_sn
For nested domains, e_we and e_sn must be one greater than an interger multiple of the nest’s parent_grid_ratio. This is to ensure that a nest always starts and ends on a parent grid point. (i.e., e_we=n*parent_grid_ratio+1 for some integer n).
It is recommended to have domains no smaller than about 100x100. Note that there will be about 10 grid points (minimum of 5) on each side, in the boundary zone. If domains are too small, the solution will be determined by forcing data. Child domains should contain similar number of grid cells as the parent.
Possible available resolutions are 10m (~19km), 5m (~9km), 2m (~4km), and 30s (~0.9km).
When there are multiple resolutions available for geographical input data, choose a resolution that is slightly better than your grid resolution. For example, if your grid resolution is 9km, using 2 minute static data would be ideal.