There're 2 differnt ncl tools.
Both were tested with ncl version 6.6.2.

ncl_itp:  use ncl build-in interpolation to convert sflux prc into vsourth.th
          Ideal for shorter length record (< 5 days).

ESMF_itp: use ESMF_regridding to interpolate prc into vsourth.th 
          Ideal for longer length record (> 30 days).

Check README for more details in each folder 
