Post Processing of ice/ocean tripole to regular lat lon

Three steps:
1) Generate the tripole fixed grid containing all stagger locations
and their vertices. Use gen_fixgrid.F90. This creates grid tripole.mx025.nc

2) Generate the interpolation weights to go from stagger locations to 
center locations and from center locations to regular lat lon. The
unstagger weights can be checked with check_weights.ncl

Steps 1 and 2 need be done only once for a given tripole grid

3) Regrid the fields using ocnpost.ncl. One complete ocn file takes
about in 188.455 seconds


?? Potential additional fields needed (some derived):
(from /scratch3/NCEPDEV/marine/noscrub/Denise.Worthen/EMC_ugcs/post/mom6_regrid/sorc):

! 5.  40=Geometric Vertical velocity (2)
! 6.  124=Momentum flux, u component (2)
! 7.  125=Momentum flux, v component (2)
! 15. 188=Evaporation - Precipitation (2)
! 16. 202=Total downward heat flux at surface (downward is positive) (129)
! 19. 197=Ocean Heat Content (129)
! 20. 194=Tropical Cyclone Heat Potential (129)
! 21. 195=Geometric Depth Below Sea Surface for the 2.5C isotherm (129)
! 22. 195=Geometric Depth Below Sea Surface for the 5C   isotherm (129)
! 23. 195=Geometric Depth Below Sea Surface for the 10C  isotherm (129)
! 24. 195=Geometric Depth Below Sea Surface for the 15C  isotherm (129)
! 25. 195=Geometric Depth Below Sea Surface for the 20C  isotherm (129)
! 26. 195=Geometric Depth Below Sea Surface for the 25C  isotherm (129)
! 27. 195=Geometric Depth Below Sea Surface for the 28C  isotherm (129)
! 32. 122=Sensible Heat (2)
! 33. 121=Latent Heat (2)
! 34. 111=Net surface Downward Short Wave flux (2)
! 35. 112=Net surface Downward Long Wave flux (2)
! 36. 59=Precipitation (2)
! 37. 57=Evaporation (2)