[netCDF] Pros of cdo

1. storage:
smaller than binary file

2. save/write nc file:
you don't need to replace the dimensions

3. tools
Nco, CDO
e.g.:
cdo selyear, 1998 XXX.nc4 example.nc4
mergetime, merge all the data
ydaymean(tas), ymonsum(prec): get the annual cycle
remapbil: resample bilinear
sellonlatbox: crop the data