[Wrf-users] Temp Advection in NCL, computation of gradients a problem

[Saji Hameed]

Hi Ryan,

You can try downloading the libraries that compute horizontal gradients
from http://www.cgd.ucar.edu/~shea/contributed.ncl_beta_640

I don't know what kind of grid your data is on - perhaps you may have to
regrid it to a regular grid.

As for the plotting, maybe you should try RasterFill first.  It may help to
smooth the data a bit before calculating the gradients (or remove any
potential
discontinuities in the original field).

For the calculation of advection, you should multiply with -1.0 to get the
right sign.

saji


Saji N Hameed,
Environmental Informatics,
University of Aizu, Tsuruga, Ikki-machi,
Aizuwakamatsu-shi, Fukushima 965-8580,
Japan

Tel: +81242 37-2736
Fax:+81242 37-2760
 email: saji at u-aizu.ac.jp
 url: http://enformtk.u-aizu.ac.jp
 bib: http://www.researcherid.com/rid/B-9188-2009
code: https://github.com/sajinh

On Fri, Apr 22, 2016 at 6:09 AM, Ryan Connelly <rconne01 at gmail.com> wrote:

> Hi fellow WRFers,
>
> Does anyone have a sample script for calculating temperature advections in
> NCL?  (Note that I'm stuck using V6.1.2, so the NCL function
> advect_variable can't be used.  Regardless, it only runs on globally
> gridded data, which this is not.)
>
> I'm trying to just hard code it like, temp_adv = u_plane*dTdx +
> v_plane*dTdy
> where u_plane and v_plane are declared using the wrf_user_intrp3d function
> .
>
> The problem I've run into is the calculation of the gradient variables
> dTdx and dTdy.  Using NCL's center_difference_n function produces
> numbers, though unrealistic, and the script ultimately crashes on
> wrf_contour by hanging up but not throwing any error.
>
> I've already posted to the ncl-talk list serv, where it was suggested that
> I try this list instead.
>
> Thanks,
> Ryan
>
> --
> Ryan Connelly
> M.S. Student in Atmospheric Sciences, Stony Brook University
> B.S. in Meteorology with Minors in Mathematics and GIS, Valparaiso
> University
> rconne01 at gmail.com
> ryan.connelly at stonybrook.edu
>
> _______________________________________________
> Wrf-users mailing list
> Wrf-users at ucar.edu
> http://mailman.ucar.edu/mailman/listinfo/wrf-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.ucar.edu/pipermail/wrf-users/attachments/20160422/d6dbab57/attachment.html