[ncl-talk] height issue

[ali mughal]

Dear NCL users

I reported this issue a few days ago.

if I subtract the terrain height from the code by adding the following step



ter=  wrf_user_getvar(a, "ter",-1)
nheight = conform(z,ter,(/0,2,3/))
z_agl = z-nheight

do level=0, nlevels-1

 height=levels(level)


u_plane = wrf_user_intrp3d( u,z_agl,"h",height,0.,False)
v_plane = wrf_user_intrp3d( v,z_agl,"h",height,0.,False)
ta_mean_plane = wrf_user_intrp3d(ta_mean_a ,z_agl,"h",height,0.,False)

I get the following plot

[image: image.png]


As you can see there is change in the field compared to the plots I shared
earlier but white spaces are removed.

Now I am not able to understand what is causing the white spaces earlier
and why they are removed when I subtract the terrain height.

In the following example, a similar procedure is followed, however, the
only difference between my code and the one in the example is the wrf file
used in the example is for multiple time steps while I am using a file
which is generated with cdo as an hourly average.

https://www2.mmm.ucar.edu/wrf/OnLineTutorial/Graphics/NCL/Examples/LEVELS_INTERP/wrf_Height.ncl








On Fri, Jan 21, 2022 at 6:58 PM ali mughal <mughalali655 at gmail.com> wrote:

> Dear NCL community
>
> I attach the output from two ncl scripts. The first one
> (Seabreeze_hourly_Ind_avg.png)  interpolates temperature and wind field to
> the first pressure level from WRF out file. If I convert the pressure level
> to the height in m it comes out to be 10 m. The 2nd output I obtain by
> using the following method instead of using the first pressure level
>
> levels = (/30.,35.,40.,45.,50.,55.,60.,65.,70.,75.,80.,85.,90./)
> nlevels=dimsizes(levels)
>
> do level=0, nlevels-1
>
>   height=levels(level)
>   u_plane = wrf_user_intrp3d( u,z,"h",height,0.,False)
>   v_plane = wrf_user_intrp3d( v,z,"h",height,0.,False)
>   ta_mean_plane = wrf_user_intrp3d(ta_mean ,z,"h",height,0.,False)
>   U_1=u_plane(0,:,:)
>   V_1=v_plane(0,:,:)
>  ta_mean_1=ta_mean_plane(0,:,:)
>  tc2=ta_mean_1-273
>
> As you can see that the first level is 30m, considerably higher than the
> first pressure level but in the first plot, there are no white spaces which
> mean every thing is plotted above the terrain while in the second plot
> there are white spaces meaning these are points below the terrain.
> Can someone kindly let me know how I can remove this difference ?
>
> Regards
>
> Ali
>
>
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