CDO

Hi Serge,

you can write a short shell script to loop over the months, select the first and last day and use divdpm to devide the result by the number of days per month.

Example ksh-script snippet (for convenience delete February 29th, use calendar 365_day):

orgfile=infile.nc

cdo -del29feb $orgfile tmp.nc

set -A dpm 31 28 31 30 31 30 31 31 30 31 30 31

typeset -i j=1

for ((i=0; i<=11; ++i))
do
   echo "-- month  $i - days ${dpm[${i}]}" 
   cdo selmon,${j} tmp.nc m_${i}.nc
   cdo -divdpm -sub -selday,${dpm[${i}]} m_${i}.nc -selday,1 m_${i}.nc o_${i}.nc
   j=++j
done

cdo -O mergetime o_*.nc outfile.nc

rm -rf m_*.nc o_*.nc tmp.nc

-Karin

Thank you a lot Karim, my data is noleap data. so don't need to delete anythings.
but I didn't understand the line typeset -i j=1;

could you explain it to me.
thank you in advance

As mentioned above it is a part of a Korn Shell script which you can run in a terminal. It is just an example how you could do it. The line 'typeset -i j=1' defines an integer variable j and initialize it to one. If you are unfamiliar with shell scripting you will find enough tutorials about it all around, but not here. Sorry.