How to increasing the eta levels near the surface ?

[+pomp953407]

Dear all,

I want to make the first layer of WRF output file to the lowest acheieving only 10 meters near the surface ( or smaller than 10 meters) .
What is the best way to do it ?
How to set the eta_levels ?
Or this scenario can't be done at all.
I have tried so many ways to do it but all of the results are worse .
Because the terrain is complex in Taiwan, the model can't operate at all early.

thank you .

 

[Ming Chen]

A better way to do so is to run REAL program first to produce eta levels. Based on the automatically generated eta levels, you can add extra levels in lower atmosphere. For example, suppose REAL produces the following eta levels:
eta_levels = 1.00000 , 0.99 , 0.98 , 0.97 , 0.95 , ....
You can explicitly specify eta_levels in namelist by setting
eta_levels = 1.00000 , 0.997 , 0.994, 0.99, 0.987 , 0.984, 0.98, ...,
You can always adjust the levels based on your specific case.

 

[FC_Stl_90]

The question is which file should I edit and how to edit it?
After running REAL, wrfinput and wrfbdy is generated. How can I see the eta levels? Then do I just edit nameless.input and put the same amount of numbers after eta_level=/....../ ? Thank you.

 

[Ming Chen]

After running REAL< you will produce wrfinput and wrfbdy files. in wrfinpu, you can find the variables below:
float ZNW(Time, bottom_top_stag) ;
ZNW:FieldType = 104 ;
ZNW:MemoryOrder = "Z " ;
ZNW:description = "eta values on full (w) levels" ;
ZNW:units = "" ;
ZNW:stagger = "Z" ;
float ZNU(Time, bottom_top) ;
ZNU:FieldType = 104 ;
ZNU:MemoryOrder = "Z " ;
ZNU:description = "eta values on half (mass) levels" ;
ZNU:units = "" ;
ZNU:stagger = "" ;
Look at these variables and manage to adjust them so that you have more levels in PBL.