CDO

hi!

I think yhourmean is the operator you are looking for.

hth
ralf

Hi Ralf,

so should I use this command?. Do you know if there is another flag to output in 366*4 and 365*4 time steps? Thanks in advance for all your help

cdo yhourmean,6hour infile.nc outfile.nc

If you use 366 days calendar you might want to delete the 29Feb first. you can to this in same command line with the del29feb operator:

cdo -yhourmean -del29feb infile.nc outfile.nc

BTW: yhourmean does not take an argument because it just takes into account the hours of the input file. in your case it is 6-hourly-date, so it sticks to 6-hourly values. I think this should be fine for you, but please double check with analytic test cases or something like that. I used

cdo -s -infov -yhourmean -selyear,2001/2006 -del29feb -settaxis,2000-01-01,12:00:00,6hours -seq,1,$((365*4*10))

do simulate 6hourly input and the yhourmean operation on it.

hth
ralf

Hi Ralf,
I have tried to use that command but something it feels a bit off. The output data is extremly heavy. As I mentioned before I have yearly data which I want to convert to climatology. In particular, I have 10 files (3.5G each). I tried to merge those files, but the output was about 130GB. Therefore, I decided to run this command

cd mergetime -yhourmean infile*.nc (ie. file_2005...2014.nc) outfile.nc

Since I did not get any error, I thought I would get a file about 3.5GB. The process has not finished yet and the file has already surprass the 60GB

hi again!

Just to get this clear: with climatology you mean a 6-hourly-dataset, where each timestep is the mean value of all year from the exact same timestep (like 31.01 - 18:00). correct?

mergetime is not needed if your inputs are in temporal order already. This just creates additional work. you call

cdo mergetime -yhourmean infile*.nc

does not work, because yhourmean takes only a single input stream and mergetime takes an arbitrary number of files. Another this is the operator order: They are applied from right to left. So -mergetime -yhourmean is the reverse order of what you want.

Assuming that the files have reasonable names, which enforce the correct temporal order using a wildcard, you can use cat like this:

cdo -yhourmean -cat 'infile*.nc' output.nc

or

cdo -yhourmean -cat [ infile*nc ] output.nc

Hi Ralf,

thanks so much for your help. Now, it  is working perfectly fine.

Best regards,

Estanislao