# 2D simulation with WRF-LES

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#### Kyoungock

##### New member
Hi,

I want to try to a 2D idealized case simulation with WRF-LES. (I'm using the WRF model ver. 3.8)

I checked the 2D version of the WRF model (em_grav2d_x, em_hill2d_x,.... etc) and I found that "e_sn=3" is used for x-z 2D simulation in namelist.input files (ex, /WRFV3/test/em_grav2d_x/) of those versions.
I also found "! For 2D test, call randx outside I-loop" in /WRFV3/dyn_em/module_initialize_les.F at line 531.
I'm wondering if I can use WRF-LES for conducting 2D simulation with "e_sn=3" in namelist.input and some changes (written at line 531) in module_initialize_les.F.
And, if it is possible, could you recommend a boundary condition option for 2D WRF-LES?

Kyoungock,

The WRF model is not really aware if the model is 3d or 2d. As you noted, we process 2d domains by making a really thin second horizontal dimension. Here are a few suggestions to get you started.

Set the namelist value for the south-north dimension to be 3.
Code:
``e_sn                                = 3,``

For the dimension with size 3, set that boundary condition to periodic:
Code:
``periodic_y                          = .true.,``

There are some assumptions in the initial conditions about south-north slices being identical. Users can just average those values, and make each "j" the same for each (i,k) location: field(i,j=1,k) = field(i,j=2,k) = field(i,j=3,k).

Your input.sounding file needs to have v=0.