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

[Ryan Connelly]

Hi Saji,

Hopefully I would have at least figured out the sign error eventually!

It seems like the grad_latlon_cfd function will work once I convert from
curvilinear grid to rectilinear, which seems straightforward enough with
NCL's ESMF regridding function.

Thanks!
Ryan

On Thu, Apr 21, 2016 at 7:47 PM, Saji Hameed <saji at u-aizu.ac.jp> wrote:

> 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
>>
>>
>


-- 
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
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