Change resolution of half-degree netCDF to quarter degree netCDF using nco tools

I can change the resolution of a netCDF file to a coarser one by doing something like this:

ncks --dmn lon,0,1384,5 --dmn lat,0,583,4 original.nc reduced.nc

How do I go the other way? I.e. change resolution of coarser scale netCDF to finer scale?

Answer

Increasing resolution with NCO requires regridding, available in NCO 4.5.1+. This currently requires you have a SCRIP/ESMF-compliant mapfile, which can be generated from SCRIP-compliant gridfiles with, e.g., ESMF_RegridWeightGen. You would need to install ESMF, a simple package on many free OS’s, e.g., on MacPorts ‘port install esmf’.