Improve error handling in the orog code

[GeorgeGayno-NOAA]

The orog code has a routine that checks for NetCDF i/o errors. However, it does not stop processing if an error is detected - it just prints the error to the log file.

  subroutine netcdf_err( err, string )
      integer, intent(in) :: err
      character(len=*), intent(in) :: string
      character(len=256) :: errmsg
      include "netcdf.inc"

      if( err.EQ.NF_NOERR )return
      errmsg = NF_STRERROR(err)
      print*, trim(string), ': ', trim(errmsg)

      return
    end subroutine netcdf_err

I suspect that programmers have been calling this routine with the expectation that the program will stop if there is an error.

[GeorgeGayno-NOAA]

As a test, I commented out the copy of the gmted2010 data to the working directory in fv3gfs_make_orog.sh

diff --git a/ush/fv3gfs_make_orog.sh b/ush/fv3gfs_make_orog.sh
index 6fcff667..4ae30615 100755
--- a/ush/fv3gfs_make_orog.sh
+++ b/ush/fv3gfs_make_orog.sh
@@ -83,7 +83,7 @@ cd $workdir

 cp ${indir}/topography.antarctica.ramp.30s.nc .
 cp ${indir}/landcover.umd.30s.nc .
-cp ${indir}/topography.gmted2010.30s.nc .
+#cp ${indir}/topography.gmted2010.30s.nc .
 if [ $inorogexist -eq 1 ]; then
    cp $inputorog .
 fi

This should result in an error.

Running the regression tests showed the open of this file failed, the error handler was called, but processing continued. The 'oro' files contained zeroes for the terrain height.

  Attempt to open/read UMD 30sec slmsk.
  UMD lake, UMD(50,50)=    0
  Call read_g to read global topography
 Open file topography.gmted2010.30s.nc: No such file or directory
 Inquire varid of topo: NetCDF: Not a valid ID
 Read topo: NetCDF: Not a valid ID

 global0 max=           0  min=           0  sum=                     0
  i_count_notset=           0
 global0 mean=                     0  std.dev=                     0  ko9s=
   933120000           0   933120000
  After read_g, glob(500,500)=      0

[GeorgeGayno-NOAA]

Rerunning the above test with the fix at 33a8df2 shows the program stops, as it should:

  UMD lake, UMD(50,50)=    0
  Call read_g to read global topography
 FATAL ERROR: Open file topography.gmted2010.30s.nc: No such file or directory
abort:

real    0m0.288s
user    0m0.013s
sys     0m0.258s
+ iret=134