[ncl-talk] WRF Cross-section Plot - Terrain Depiction and Lowest Level Data Contours

[Bill Ladwig]

Hi Scott,

My first guess is that the vertical levels for interpolation are too large
(not your fault). The interpolation algorithm automatically chooses
vertical levels at .01*z_max. In your case z_max is 20251.8 m, which means
your interpolation levels are at 202.5 m per grid box. This is probably too
large for what you're interested in looking at.

As a first attempt to fix, let's edit your WRFUserARW.ncl.

At line 383, change this:

dz = 0.01 * z_max
>

to this:

dz = 0.0025 * z_max


If this doesn't help your situation, I'll need to dig in to this a bit more.

Hope this helps,

Bill

On Thu, Jan 18, 2018 at 3:04 PM, Scott Capps via ncl-talk <ncl-talk at ucar.edu
> wrote:

> Greetings,
>
> I have some questions about the cross-section plots from WRF output.  I
> basically started from the example scripts at:  http://www2.mmm.ucar.edu/
> wrf/OnLineTutorial/Graphics/NCL/Examples/CROSS_SECTION/
> wrf_CrossSection_smooth4.htm
>
> The whitespace along the terrain height is much too large and the terrain
> is too coarse (this is a 667m resolution WRF run) or the lowest level
> atmospheric data is not being contoured correctly.  The cross-section
> plotting routine in GRaDs seems to show true the resolution of terrain and
> terrain following data.  Is there a way to improve this in NCL?
>
> I have attached some code (cross_sxn_plot_test.ncl and modified
> WRFUserARW.ncl) and have ftp'd an example wrfout file to the incoming
> directory as:  wrfout_d05_2017-10-09_00:00:00.nc
>
>
> NCL v6.3.0
> http://www2.mmm.ucar.edu/wrf/OnLineTutorial/Graphics/NCL/
> Examples/CROSS_SECTION/wrf_CrossSection_smooth4.htm
>
> --
> *Scott Capps*
> Principal
> Atmospheric Data Solutions <http://www.atmosphericdatasolutions.com>
> scapps at atmosdatasolutions.com
> cell: (949) 910-4385
>
>
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