SOSIE

"SOSIE is a tool that allows fast and high-quality 2D and 3D interpolation of geophysical fields from a gridded domain to another. "Sosie" is the french word for "double" (like in look-alike). SOSIE is developed and distributed under the GNU General Public License (GPL). 

SOSIE was originally intended to interpolate geophysical fields onto the ORCA family of tri-polar grids used by the NEMO ocean general circulation model (ORCA2, ORCA1, ORCA05, ORCA025). It now supports a wide range of source/target grid configuration for scalar fields interpolation but vector rotation in distorted target grid regions is only supported for the ORCA grids so far.

The main interpolation algorithm of SOSIE is based on the method of Akima (1970): "A New Method of Interpolation and Smooth Surface Fitting Based On Local Procedures, J.of Applied Comput. Math., 17, 589-602." In SOSIE, this method has been coded from scratch in plain Fortran-90. The algorithm is made highly efficient by skipping solving a 16x16 linear system for each treated point of the target grid. Instead, a particularly efficient way to calculate the general solution of the 16x16 system was found (J.M. Brankart, personal communication).

Compared to more widely used interpolation methods such as bilinear or bicubic splines, the Akima method allows, at an extremely low numerical cost, continuous and smooth interpolated fields without errors related to overshoots (as for polynomial functions, see 1D illustrations below).
 
SOSIE can perform 3D interpolation. This is fake 3D interpolation though: each level is independently interpolated on the target horizontal domain and vertical interpolation (using Akima 1D algorithm) is then performed. SOSIE uses Netcdf as IO file format."

http://sosie.sourceforge.net/ 

https://sourceforge.net/projects/sosie/ 

http://meom-group.github.io/code/