cdo monthly mean adds extra dimension and variable
Added by Christ Reflin almost 3 years ago
Dear cdo developer,
I have 3 months of daily temperature data. Each of them has 1 variable (temperature) and 3 dimension (lon,lat,tim)
I would like to obtain monthly data by averaging the daily temperature, so at the end I would have 3 band.
in the beginning, I merged all of them using
$ cdo mergetime inputfile*.nc merge_file.nc
after that, I calculated the average of the merge_file.nc using
$ cdo monavg merge_file.nc finaldata_monthlyavg.nc
However, my finaldata_monthlyavg.nc has 2 variable and 4 dimension,
Could you help me to understand this?
Thank you
Christ
| merge_file.nc (4.22 MB) merge_file.nc | |||
| finaldata_monthlyavg.nc (173 KB) finaldata_monthlyavg.nc |
Replies (3)
RE: cdo monthly mean adds extra dimension and variable - Added by Karin Meier-Fleischer almost 3 years ago
Hi Christian,
the result is exactly what I would expect. When using monavg CDO adds the time bounds variable which has the dimensions(time,bnds).
time_bnds = 43829, 43859, 43860, 43888, 43889, 43919 ;
The time variable contains the mid points of time_bnds.
time = 43844, 43874, 43904 ;
CF-convention:
"time_bnds" is a separate 2-dimensional variable that defines the start and end time points of each measurement.
Variable "time_bnds" has the same attributes "units" and "calendar" as variable "time".
-Karin
RE: cdo monthly mean adds extra dimension and variable - Added by Christ Reflin almost 3 years ago
Thank you for your response Karin,
I really appreciate it,
Can I remove this time_bnds variable without disarrange the others variable?
How do I obtain the average months without adding the additional dimension?
Best
Christian
RE: cdo monthly mean adds extra dimension and variable - Added by Karin Meier-Fleischer almost 3 years ago
Maybe some applications need to have the time_bnds. If you want to delete the time_bnds you have to delete the attribute bounds from time, too. It points to the time_bnds variable.
To delete time_bnds do
ncks -O -C -x -v time_bnds finaldata_monthlyavg.nc outfile.nc