CDO

Hi Joao,

if I understand you correctly, this is what you want to do: select only the timesteps where tipo is equal 5
and then do a field average on msl only for that timestep. In my opinion there is no simple way but you can
write a short shell script.

Here is a Korn Shell example script which computes the fldmean for the three timesteps where tipo is equal 5,
writes each to a single file and merge all together at the end.

#!/bin/ksh

input="merged.nc" 

rm -rf tmp_*.nc

ntime=$(cdo -s ntime merged.nc)

for ((i=1; i<=$ntime; i++)) ; do
   tipo=$(cdo -s -outputint -selname,tipo -seltimestep,${i} $input)
   if [[ $tipo -eq 5 ]]; then
      echo "-- ${i}:  tipo == 5   fldmean" 
      cdo -s -fldmean -selname,msl -seltimestep,${i} $input tmp_${i}.nc
   else
      echo "-- ${i}:  tipo != 5" 
   fi
done

cdo -O mergetime tmp_*.nc outfile.nc

exit

-Karin

Hi!!

Thanks for your answer… Instead of field average I want a time average on all gridpoints but only for those timesteps where tipo=5

Meanwhile I found an elegant and compact way to do it:

cdo expr,"var=msl/(tipo==5)" input output -> it populates "var" with the original msl for the times where tipo=5 and NaN for tipo diferent from 5
cdo timmean output output_mean -> it calculates the time mean not taking into account the times where msl is NaN

Regards

Joao

Sorry, I missed that word 'temporal'. To make it perfect combine the two cdo calls.

cdo -timmean -expr,"var=msl/(tipo==5)" merged.nc outfile2.nc