Dear Ferret users,
I computed composites of the geopotential by selecting specific days only (using Ferret condition IF (....) then .... ), and created a file with only these days (thus it's continuous serie but the calendar is not continous are there are gaps in the days)
I then computed the time-mean from the composites with CDO (cdo -timmean .....) and Ferret ( L=@ave ) and I can notice strong differences between the 2 results (attached, left is CDO and right is Ferret). It's not just the magnitude, also the patterns differ (though the main signal is quite close), which is really strange.
I dont know if it's a Ferret or CDO problem, or if it comes from the gaps in the calendar of the composites... But even so, the patterns should at least look similar.