Re: uv2dvF and uv2vrF NaN values

Hi Mary,
I've been digging into this and believe I have found the issue with returns of NaNs.
It seems that the input arrays that were being fed to these functions have some 'inf and -inf' values in a few grid cells.
I re-created the input files so no 'inf' values were included and the functions seem to be working normally (although plotting even a single panel is painstakingly long which I'm guessing is a product of the very small values of vorticity and divergence and the precision of the contour levels needed????).
It seems the functions saw some of these 'inf' values and choked?
I can send along both versions of the input files and my working .ncl code if you feel it is necessary to look into the issue further.

Thanks,Jon

> Subject: Re: uv2dvF and uv2vrF NaN values
> From: haley@ucar.edu
> Date: Thu, 20 Feb 2014 08:53:37 -0700
> CC: ncl-talk@ucar.edu
> To: tallj03@hotmail.com
>
> Hi Jon,
>
> If *any* NCL function is returning NaN, this is a problem. They should be returning missing values or else issuing some kind of error.
>
> Can you provide the two NetCDF files online? You can use our ftp:
>
> http://www.ncl.ucar.edu/report_bug.shtml#HowToFTP
>
> --Mary
>
>
> On Feb 19, 2014, at 3:50 PM, jonathan meyer <tallj03@hotmail.com> wrote:
>
> > Good afternoon NCL-ers,
> >
> > I am computing ageostrophic winds using actual winds and geostrophic winds. In order to convince myself the ageostrophic wind fields satisfy the mathematics of the atmosphere I am computing the divergence and vorticity of the ageostrophic winds which should equal zero everywhere.
> >
> > Using the uv2dvF and uv2vrF functions to compute these two fields returns NaN values for the entire array. I've confirmed there are no missing data, and the dataset is on a global fixed grid with the latitude monotonically increasing (-90 to 90).
> >
> >
> >
> > My question:
> >
> > Is the return of NaN an artifact of the functions where divergence/vorticity is actually zero?
> >
> > I've tested these functions using actual U and V winds and they return appropriate ranges of values, so something is unique to the ageostrophic winds.
> >
> > Thanks in advance,
> > Jon
> >
> >
> > My Code Snippet
> >
> > begin
> > ;==================================================================
> > print("ESTABLISH CCSM FILES AND RETRIEVE DIMENSION INFO")
> > ; =================================================================
> >
> > f1_in = addfile(dir1 + "CCSM_REG_U_test1979.nc", "r")
> > f2_in = addfile(dir2 + "CCSM_REG_V_test1979.nc", "r")
> >
> > lev = f1_in->lev
> > lat = f1_in->lat2(::-1)
> > lon = f1_in->lon2
> >
> > n_lev = dimsizes(lev)
> >
> > ; =================================================================
> > print("READ IN CCSM DATA")
> > ; =================================================================
> >
> > Ug = f1_in->Ug(:,:,::-1,:)
> > U = f1_in->U( :,:,::-1,:)
> >
> > Vg = f2_in->Vg(:,:,::-1,:)
> > V = f2_in->V( :,:,::-1,:)
> >
> > ; =================================================================
> > print("COMPUTE AGEOSTROPHIC WINDS")
> > ; =================================================================
> >
> > Ua = U-Ug
> > Va = V-Vg
> >
> > ; =================================================================
> > print("COMPUTE DIVERGENCE AND VORTICITY OF AGEOSTROPHIC WINDS")
> > ; =================================================================
> >
> > print(num(ismissing(Ua)))
> > print(num(ismissing(Va)))
> >
> > div = uv2dvF(Ua,Va)
> > vor = uv2vrF(Ua,Va)
> >
> > ****RESOURCE SETTING BLAH BLAH*******
> >
> > do z = 0, n_lev-1
> > print("Plotting level " + lev(z))
> >
> > resdiv@gsnCenterString = "Divergence"
> > plot(0) = gsn_csm_contour_map_ce(wks, div(0,z,:,:), resdiv)
> >
> > resvor@gsnCenterString = "Vorticity"
> > plot(1) = gsn_csm_contour_map_ce(wks, vor(0,z,:,:), resvor)
> >
> > resP@txString = "00Z 1 July 1979 "+ lev(z) + "-mb"
> > gsn_panel(wks,plot, (/2,1/), resP)
> >
> > end do
> >
> >
> > end
> >
> >
> >
> > When Running the code:
> >
> > See http://www.ncl.ucar.edu/ for more details.
> > (0) ESTABLISH CCSM FILES AND RETRIEVE DIMENSION INFO
> > (0) READ IN CCSM DATA
> > (0) COMPUTE AGEOSTROPHIC WINDS
> > (0) COMPUTE DIVERGENCE AND VORTICITY OF AGEOSTROPHIC WINDS
> > (0) 0
> > (0) 0
> > (0) Plotting level 30
> > warning:ContourPlotInitialize: no valid values in scalar field; ContourPlot not possible:[errno=1101]
> > warning:ContourPlotInitialize: no valid values in scalar field; ContourPlot not possible:[errno=1101]
> > (0) Plotting level 50
> > warning:ContourPlotInitialize: no valid values in scalar field; ContourPlot not possible:[errno=1101]
> > warning:ContourPlotInitialize: no valid values in scalar field; ContourPlot not possible:[errno=1101]
> >
> >
> >
> >
> >
> >
> > _______________________________________________
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>
                                               

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Received on Fri Feb 21 12:28:42 2014