Using nco 4.0.8, I have found a new problem that was not in 4.01
when I want to cat 2 files that have different time origin.
$ ncdump -h f1.nc | grep since
time:units = "days since 1850-01-01 00:00:00" ;
$ ncdump -h f2.nc | grep since
time:units = "days since 2006-01-01 00:00:00" ;
$ ncrcat -D1 -Oh f1.nc f2.nc tyty.nc
ncrcat: INFO Build compiler lacked (or user turned off) OpenMP support. Code will execute with single thread in Uni-Processor (UP) mode.
ncrcat: TIMER Metadata setup and file layout before main loop took 0.00 s
ncrcat: INFO/WARNING Inter-file non-monotonicity. Record coordinate "time" does not monotonically increase between last specified record of previous input file (whose name is not cached locally and thus currently unavailable for printing) and first specified record (i.e., record index = 0) of current input file (f2.nc). This message is often informational only and may usually be safely ignored. It is quite common when joining files with "wrapped" record coordinates, e.g., joining a January file to a December file when the time coordinate is enumerated as day of year. It is also common when joining files which employ a "time=base_time+time_offset" convention. Sometimes, however, this message is a warning which signals that the user has joined files together in a different order than intended and that corrective action should be taken to re-order the input files. Output file tyty.nc will contain these non-monotonic record coordinate values (56924.500000, 15.500000) at record indices 1871, 1872.
ncrcat: INFO Moving tyty.nc.pid10995.ncrcat.tmp to tyty.nc...done
ncrcat: TIMER Wallclock-elapsed time for command is 0.10 s
--> the resulting file has a "time" variable and its bounds "time_bnds" variable not correct
in a sens that ncrcat does not calculate the offset due to the different time origin.
With 4.0.1, it was ok at least for the time variable (not the bounds).
Let me know if the feature can be covered we have to cat a lot
of heterogeneous files with different reference time (since aspect in time axis).
The 4.0.5 release has the same behaviour on this point than the 4.0.8 release.
LSCE/IPSL, Laboratoire CEA-CNRS-UVSQ
Data Analysis and Visualization Engineer
ICMC - IPSL Climate Modelling Centre
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