Hello, Amir Asadi Vaighan,

Unfortunately, I am not familiar with CDO, but I have experience with processing data from .nc files using Python (installed on Linux machine), so, if necessary, I may try to help with them using these tools.

Also, I cannot download your example files...

Best regards,

Aleksei V.

Dear Aleksi

I've manged to calculate these values very easy in CDO, very convenient software under linux and very fast.

Thanks.

Hello Amir,

Let's say that you have a historical precipitation nc file with 30 years of monthly data (p.his.nc) with 360 time-steps. And another file with same characteristics but for future data (p.fut.nc). So a dummy way to calculate Delta P (%) is as follows:

cdo sub p.his.nc p.fut.nc numerator.nc this is the subtraction P(hist)-P(fut)

cdo div numerator.nc p.fut.nc delta.p.nc this is Delta P value

cdo -expr,'var=var*100' delta.p.nc percentage.delta.p.nc this express in %

var: meaning the name of the variable of precipitation of delta.p.nc. You can check file information using ncview commands. For temperature delta the estimation is similar. I'm using cdo install for ubuntu. You can also check cdo pages and tutorials, https://code.mpimet.mpg.de/.

Regards,

Leandro.-

Hi Leonardo

Thanks for the guide, that's what I did exactly in CDO, its very easy to work with large data.

Cheers

Amir