Re: wrf_uvmet and missing values

Hi Melissa,

wrf_uvmet doesn't check for missing values, and hence it doesn't
handle them at all.

I'm puzzled as to how your values can be changing when you change the
missing value, because this value is
not used by the underlying Fortran code.

Having said this, however, I noticed that wrf_uvmet returns a default
missing value, which is -999 for floats, and -9999 for doubles.
Maybe this is affecting things, but I don't see how.

Can you provide me with a pared down version of your script that shows
the problem, and your data?
  (Email me offline about this).

--Mary

On Jun 15, 2010, at 1:10 PM, Melissa A Richards wrote:

> Hello,
>
> I was wondering how wrf_uvmet handles missing values.
>
> I have a wrf output file that has been made cf compliant (run
> through the wrfout_to_cf.ncl program). This has unstaggered the
> variables and interpolated vertical variables to pressure levels
> (i.e. 850 mb, 700mb, etc.).
>
> I can read in this file and rotate 10 meter winds with no problems.
> When I attempt to rotate 850 mb or 700 mb winds I run into a
> problem. It seems that wrf_uvmet is using the missing values
> (@_FillValue = -999999) in the rotating calculation and therefore, I
> am getting wind speeds of 1,414,211 m/s. Note, if I change the
> missing value to @_FillValue = -999, I get wind speeds of 1,412 m/
> s. Therefore, I do believe that this is tied to the attribute
> @_FillValue. Any thoughts on how to fix this?
>
>
> Here is the relevant portion of the code.
>
> u_gr_p = wrf->u_gr_p(0,2,:,:)
> u_gr_p@_FillValue = -999999
> u_gr_p@lat2d = wrf->lat
> u_gr_p@lon2d = wrf->lon
>
> v_gr_p = wrf->v_gr_p(0,2,:,:)
> v_gr_p@_FillValue = -999999
> v_gr_p@lat2d = wrf->lat
> v_gr_p@lon2d = wrf->lon
>
> uvm = wrf_uvmet(u_gr_p,v_gr_p,wrf->lat,wrf->lon,180.,1)
>
> u = uvm(0,:,:)
> v = uvm(1,:,:)
>
> Thank you!
> Melissa
>
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Received on Wed Jun 16 08:11:39 2010