NCO provides some tools to do quick analysis on NC files.
Now, I need to calculate area-weighted average anomaly for global land surface.
Raw monthly temperature anomaly file: tmp.nc
- calculate year mean:
cdo yearmean tmp.nc in.nc
- calculate areal weight:
ncap -h -O -s “weights=cos(lat*3.1415/180)” in.nc in.nc
- calculate average:
ncwa -h -O -w weights -a lat,lon in.nc global_mean.nc