cdo

good day,

i have a file.nc with daily data in it from 1990-1992.
how can i use cdo to give the data in mothly format where the months is an average of the number of days within a month...

i have tried:

cdo ymonmean echam_amip_${var2[j]}_ensmean.nc echamMON_amip_${var2[j]}_ensmean.1980_2003.nc

pls help

thanx,

By CDO do you mean Climate Data Operators?

yes, thats it