center_finite_diff_n missing values

I'm using center_finite_diff_n on two 4D array (time, pressure, lat,
lon) with missing values. With one array, the u-wind, it handles missing
values fine. With the v-wind array, it doesn't. Both arrays have the
same metadata (missing and fill values). Any ideas why v-wind is a problem?

Code snippet:
dlat = 2.5*0.0174533
   dlon = dlat
   do n2=0,nlon-1
     dx = 6378388*cos(0.0174533*lat(n2))*dlon
     mfu(:,:,:,n2) =
center_finite_diff_n((hus(time|:,plev|:,lat|:,lon|n2)/g)*ua(:,:,:,n2),dx,False,0,2)
   end do
   dlon = 2.5*0.0174533
   do n1=0,nlat-1
     dy = 6378388.*0.0174533*dlon
     mfv(:,:,n1,:) =
center_finite_diff_n((hus(time|:,plev|:,lat|n1,lon|:)/g)*va(:,:,n1,:),dy,False,0,2)
   end do

Thanks,
Nicole

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*     Nicole Schiffer
*     Graduate Research Fellow (Dept. of Energy)
*     Department of Atmospheric Sciences
*     University of Illinois, Urbana-Champaign
*     Email: nschiff2 [at] illinois [dot] edu
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
_______________________________________________
ncl-talk mailing list
List instructions, subscriber options, unsubscribe:
http://mailman.ucar.edu/mailman/listinfo/ncl-talk