CDO

Hi

I could not find an information about the possible relative and absolute time units supported by cdo.

In my particular example, I have a monthly time series starting from ~7000 BP towards today. I would like that `ncview in.nc` shows a nice representation of this time series, without strange gaps on the x-axis due to a time format where jumps occur from e.g. month 12 to month 1.

I tried several things and ended up with setting an absolute time in the format `years as %Y.%f` using `ncap2` from the nco package. This throws the error `ERROR: units attribute "years as %Y.%f" is not listed in UDUnits2 SI system database` but the representation of the time series with ncview is nice, just as I want it (I also could not find a list of supported time formats of nco ncap and/or UDunits).

Now, it seems that cdo does not understand this format, as

$ ncdump -c in.nc
time:units = "years as %Y.%f" 
time: -6995.962366,-6995.876437,-6995.795699,-6995.711111, # <-- correct and works for nice ncview representation

$ cdo showdate in.nc 
-6994-01-01 -6993-01-01 -6992-01-01 -6991-01-01 -6990-01-01 # <-- not correct 

Do you have an idea how to show these negative dates without gaps in ncview in a time format that is correct for cdo (and nco)? Example file attached.

Thanks a lot,
Chris