Extract a year from ncdf and make it constant for the whole time series

I have a netcdf monthly data from 1960-2100. I want to extract the 1960 data and make it the same for each year. How do I do it? How to extract the 12 months in a year and replace all years? Thanks. Please let me know if it is not clear.

Replies (6)

RE: Extract a year from ncdf and make it constant for the whole time series - Added by Ralf Mueller almost 7 years ago

Hi Felix!

select the year:

cdo -selyear,1960 ifile 1960_DataFile.nc

I would then split the large file per year with
```
cdo splityear
```

loop over all years except 1960 with something like this

for year in $(seq -w 1961 1 2100); do cdo setyear,$year 1960_DataFile.nc ${year}_DataFile.nc ; done

concat all files with
```
 cdo cat '*_DataFile.nc' all.nc
```

hth
ralf

RE: Extract a year from ncdf and make it constant for the whole time series - Added by Felix Leung almost 7 years ago

Thanks for your quick reply! Why do you need to split the large file in step 2?

RE: Extract a year from ncdf and make it constant for the whole time series - Added by Ralf Mueller almost 7 years ago

good point - forget about it ;-) I was on the wrong track to the solution ....

sorry for the entropy,
ralf

RE: Extract a year from ncdf and make it constant for the whole time series - Added by Felix Leung almost 7 years ago

Thank you very much! It works!

RE: Extract a year from ncdf and make it constant for the whole time series - Added by Felix Leung almost 7 years ago

Hi Ralf,
I have tried it with a different .nc file but I got this error when I do the cdo cat
Warning (cdfInqContents) : 5 dimensional variables are not supported, skipped variable resp_s!
Warning (cdfInqContents) : 5 dimensional variables are not supported, skipped variable cs!

How to make it supported?

RE: Extract a year from ncdf and make it constant for the whole time series - Added by Ralf Mueller almost 7 years ago

it depends: 5-dims are not supported by underlying IO library CDI. I guess, you will have to use another tool like some NCO programm.

If your time axis is relative, you could simple copy the 1960-file and change the time axis meta date, i.e. the reference date

hth
ralf

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