I'm trying to merge NetCDF files with ncrcat: ncrcat drycblles.default.000* drycblles.default.nc This works fine, unless some files have overlapping times, in which case I get time records like this: t = 0, 300, 600, 900, 1200, 1500, 1800, 2100, 2400, 2700, 3000, 3300, 3600, 3900, 4200, 4500, 4800, 5100, 5400, 5700, 6000, 6300, 6600, 6900, 7200, 3900, 4200, 4500, 4800, 5100, 5400, 5700, 6000, 6300, 6600, 6900, 7200, ... CDO has an option to remove duplicate records with e.g. export SKIP_SAME_TIME=1