Re: How to specify data coordinates in wrf_contour

Hello,

I am interested in getting data coordinates in 2D simulations, particularly
to the output from em_hill2d_x in WRF.

The example NCL plots/script shown here
http://www.mmm.ucar.edu/wrf/OnLineTutorial/Graphics/NCL/Examples/wrf_Hill2d.htm

just plots the data contour without having the 2D X and Y data coordinates
specified.

For 100 m hill there doesn't seem to be a problem with the simulation and
plotting, however setting the mountain height to 2 km results in the model
domain top coming down (i.e. starting maximum model height ~20 km at the
end of the simulation max height is ~17.5 km). With the current NCL example
it's not possible to see this issue. Hence, I am looking for a modified way
to plot data contour in NCL.

Thanks.

On Thu, Feb 27, 2014 at 12:04 PM, Mary Haley <haley@ucar.edu> wrote:

> Hi Gökhan,
>
> wrf_contour simply draws the contours, with no map projection.
> wrf_map_overlays is what takes the contours and overlays them on a map.
>
> If you really are only interested in wrf_contour and want to specify the
> data coordinates, then you need to read XLAT and XLONG off the file (I'm
> assuming you are plotting lat/lon data), and then set the special sfXArray
> and sfYArray resources.
>
> Here's a working script that you can try, using the HGT variable on a wrf
> output file.
>
> Try it both with and without the sfX/YArray settings, to see what happens
> to the plot. The "trGridType" setting is necessary in order to get
> tickmarks. If you were putting this over a map (via wrf_map_overlays),
> then you wouldn't need trGridType:
>
>
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"
>
> begin
> a = addfile("wrfout.nc","r")
> hgt = wrf_user_getvar(a,"HGT",0)
>
> wks = gsn_open_wks("x11","mapgrid")
>
> res = True
> res@sfXArray = wrf_user_getvar(a,"XLONG",0)
> res@sfYArray = wrf_user_getvar(a,"XLAT",0)
> res@trGridType = "TriangularMesh"
>
> plot = wrf_contour(a,wks,hgt,res)
>
> draw(plot)
> frame(wks)
>
> end
>
> On Feb 27, 2014, at 5:43 AM, Gökhan Sever <gokhansever@gmail.com> wrote:
>
> Hello,
>
> Is there a way to specify X,Y coordinates of data surface within
> wrf_contour? [
> https://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_contour.shtml]
>
> Similar to how is done in matplotlib's contour function [
> http://matplotlib.org/api/pyplot_api.html#matplotlib.pyplot.contour]
>
> Thanks.
>
>
> --
> Gökhan
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>
>

-- 
Gökhan

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Received on Fri Feb 28 12:07:06 2014