CDO

Hi Michael,

the following example describes how you can do the selection. Temperature variable tsurf, precipitation variable precip

cdo -timpctl,75 -selvar,tsurf $infile \
                -timmin -selvar,tsurf $infile \
                -timmax -selvar,tsurf \
                infile.nc tsurf_75pctl.nc

cdo -timpctl,25 -selvar,precip $infile \
                -timmin -selvar,precip $infile \
                -timmax -selvar,precip \
                infile.nc precip_25pctl.nc

cdo -gt -selvar,tsurf  infile.nc tsurf_75pctl.nc  out_tsurf.nc
cdo -lt -selvar,precip infile.nc precip_25pctl.nc out_precip.nc

cdo -chname,tsurf,mask -mul out_tsurf.nc out_precip.nc masked_gtT75_ltP25.nc

cdo -timsum -mul -selvar,tsurf  infile.nc masked_gtT75_ltP25.nc outfile_tsurf.nc
cdo -timsum -mul -selvar,precip infile.nc masked_gtT75_ltP25.nc outfile_precip.nc

-Karin

I'm note sure, but I think is missing something in the last command:

cdo -timsum -gtc,0 -mul -selvar,tsurf infile.nc masked_gtT75_ltP25.nc outfile_tsurf.nc
cdo -timsum -gtc,0 -mul -selvar,precip infile.nc masked_gtT75_ltP25.nc outfile_precip.nc

The question would not be to know the sum of occurrences? I put gtc,0.

Karin and Guilherme, thank you so much for your help.

Guilherme, what is the difference between putting "gtc,0" in the last line?

Good point. Guilherme is right, you are looking for the "sum of occurrences of an event where Precipitation < P25 and Temperature > T75".

The result of my approach is the sum of the data values when the condition is True. The operator -gtc,0 creates a mask where the value is 1 if the condition is True or 0 if False. The timsum then sums it up (count) the occurences.

Thank you so much, I appreciate it.