Generating indices
Added by Matt Hyde about 1 year ago
Hi
I have a netcdf file data.nc which has the monthly values like sst for all gridcells from 2000 to 2020. I want to generate indices like Nino3.4 and Indian Ocean DMI using CDO. How is it possible to do it?
Replies (1)
RE: Generating indices - Added by Karin Meier-Fleischer about 1 year ago
Hi Matt,
first, I'm not an expert, but you can compute the El Nino 3.4 index as follows
1. compute the climatology for a 30-years time range
cdo -ymonmean -selyear,1971/2000 -sellonlatbox,190.,240.,-5.,5. infile.nc clim.nc
2. compute the anomaly
cdo -sub -sellonlatbox,190.,240.,-5.,5. infile.nc clim.nc anom.nc
3. compute the Nino 3.4 index
cdo -div anom.nc -timstd anom.nc el_nino3.4_index.nc