[ferret_users] when a /append causes a "** netCDF error: Variable not found"

[Brockmann Patrick <Patrick.Brockmann@xxxxxx>]

Hi all,

I have encoutered a weird problem with an save/append command.
ferret fails and complains about a " ** netCDF error: Variable not found"
after a certain limit has been reached.
It was not easy to find and to isolate but here are the facts

! file_part1.nc has 360 time steps
use "file_part1.nc"            
let var2=var1
save/file="fileout.nc"/clobber var2

! file_part2.nc has 840 time steps
use "file_part2.nc"           
let var2=var1
save/file="fileout.nc"/append/l=361:840 var2
LISTing to file fileout.nc
** netCDF error: Variable not found
failure writing to CDF output file

when file_part2.nc has only 720 time steps
it works !

The general context is to compute a weighted global average
of a 2D variable following the progress of the simulation
(300 years with a monthy frequency). This for a lot of variables.

Tested with a ferret v6.20 (Linux 32bits).

The complete bug  materials can be found from
http://dods.ipsl.jussieu.fr/brocksce/ferret_bugs/err620_append/

PS: If I remove the time axis (ncks -O -C -v VAR1) the error disappears.

Patrick