Assigning Vertical levels before running wrf.exe

[midhunmachary]

Hello,
I am currently working on simulation of fog using WRF model. I want to change number of Vertical levels associated with the model such that ten layers below 1000m from surface.
It will be very helpful if anyone can help me how to do it ?

Thanks in Advance,
Midhun M
Central University of Rajasthan
India

 

[asyed6]

Dear Midhun,
I had the same issue and WRF help solved my problem by responding this:

To increase vertical levels below a specific height, I would suggest you run REAL program first to create eta levels. Then you can manually increase the number of levels based on the automatically generated eta levels by REAL. For example , suppose you run REAL and get the following eta levels:
eta_levels =
1, 0.993, 0.983, 0.97, 0.954, 0.934, 0.909, 0.88,
....
....
/
You can then replace the first several eta levels by:
1, 0.999, 0.998, 0.996, 0.993, 0.990, 0.980. 0.970, 0.960, 0.950,
0.940, 0.930, 0.920, 0.910, 0.900, 0.890, 0.880, 0.870,

This is just an example to show how to add more levels within certain height

Once wrfinput is produced, you will find PH and PHB in wrfinput, and (PH=PHB) is the geopotential height corresponding to model levels.

Hope this helps.

Regards,
A. Syed

 

[midhunmachary]

Thank you for the help.
I added these two lines to the namelist.input file, before running real.exe and wrf.exe

e_vert = 45, 45, 45,
eta_levels = 1.000, 0.998, 0.996, 0.994, 0.991
0.989, 0.986, 0.982, 0.977, 0.971,
0.965, 0.958, 0.951, 0.944, 0.936,
0.929, 0.922, 0.910, 0.899, 0.880,
0.865, 0.807, 0.765, 0.719, 0.672,
0.622, 0.571, 0.520, 0.468, 0.420,
0.376, 0.335, 0.298, 0.263, 0.231,
0.202, 0.175, 0.150, 0.127, 0.106,
0.088, 0.055, 0.040, 0.020, 0.000

Now I am getting more vertical levels. I want these eta values converted to vertical height in km. Please help me to convert eta values to km.
I have attached the entire namelist file for reference.
Hope someone will help me soon.

Thanks in advance,

Midhun M AcharyView attachment namelist.input

 

[asyed6]

You can use wrfout file to calculate model heights with NCL, which has a predefined variable "Model height (z)". http://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_user_getvar.shtml
It will give you model height corresponding to eta levels in "m".

Hope this helps.

 

[janac4]

Hello,
I'm trying to understand eta levels and found your post to convert them into meters. Wrf-python returns z variable but it isn't estationary in space, which is logical, but since eta levels are saved in ZNU variable with bottom_top as the only dimension, is there a way to find a variable in meters that refers to that same levels? So that when we talk about bottom_top index = 10 we know it is at 100hPa or 10km for example, without spatial dependence.