Increase Eta level and decrease dzbot -

[L Alvarez]

Hello there,

I need to increase my number of eta vertical levels, increasing the levels to low levels.
What appears below works, but if I decrease the dzbot to 15, 20 or 30, the WRF model always stops. I have also modified these parameters dzstretch_s and dzstretch_u, but without success.

e_vert = 45,45,45,45,
p_top_requested = 5000,
!sfcp_to_sfcp = .true.,
auto_levels_opt = 2,
max_dz = 1000,
dzbot = 50,
dzstretch_s = 1.5,
dzstretch_u = 1.3,

Modify this part, is it related to the time step or the resolution of the domain?..
Anyone have a configuration that works with high resolutions eta levels and a low dzbot?..

Best regards,

L Alvarez

 

[L Alvarez]

Please, any help with this issue?..

L Alvarez

 

[Ming Chen]

These options determine the vertical resolution of the model.
What is the error message when WRF crashed? Please send me your namelist.input to take a look.

 

[L Alvarez]

This portion of code works

e_vert = 45,45,45,45,
p_top_requested = 5000,
!sfcp_to_sfcp = .true.,
auto_levels_opt = 2,
max_dz = 1000,
dzbot = 50,
dzstretch_s = 1.5,
dzstretch_u = 1.3,

Now, if I modify dzbot to 30 or 20... and dzstrecth_s to 1.2 o minor, for example, not work.

e_vert = 45,45,45,45,
p_top_requested = 5000,
!sfcp_to_sfcp = .true.,
auto_levels_opt = 2,
max_dz = 1000,
[b]dzbot = 30,
dzstretch_s = 1.2,[/b]
dzstretch_u = 1.3,

I don't know what the relationship between these parameters is for it to work.
The objective is to increase vertical levels in surface (more together) or increase vertical levels in surfaces and in total as well.

L Alvarez

 

[L Alvarez]

Any suggestions, experience, trick.

L Alvarez

 

[Ming Chen]

Hi,
I am sorry for the late answer. Somehow I am unaware that this post is skipped.
dzbot is the thickness of the lowest model layer, in which the surface layer similarity is applied. Theoretically, the height of the first model level should be within the surface layer and the value of several tens of meters should be physically reasonable. However, note that some PBL schemes in WRF are strongly coupled with surface layer properties, and a shallow surface layer may cause problems in numerical integration. This is why we set the default value of dzbot = 50.