Changeset 4031 for branches

Need to introduce a better IF to re-fill `carteveget5km.nc' interpolation.
On checking the existence of aveget5km < 0., it must be done to the whole domain by 'root_proc'
If it is not done in this way, there are mpi issues os syncronization. For that reason, a global variable `aveget5k_glob' is defined and used