To compile:

1) create symlink to Makefile.conf for your platform (zeus, jet or AIX). For example, on zeus
   ln -fs Makefile.conf.zeus Makefile.conf

2) make sure the relevant modules are loaded on zeus and jet, i.e.

   module load intel
   module load netcdf
   module load mpt (on zeus)
   module load mvapich2 (on jet)

3) To compile global_enkf (for GFS model), edit Makefile.conf and make sure the lines

  FFLAGS_F90    = -DGFS
  EXE_FILE = global_enkf

  are uncommented, and 

  #FFLAGS_F90    = -DWRF
  #EXE_FILE = regional_enkf

  are commented out.

4) To compile regional_enkf (for WRF model), edit Makefile.conf and make sure the lines

  FFLAGS_F90    = -DWRF
  EXE_FILE = regional_enkf

  are uncommented, and 

  #FFLAGS_F90    = -DGFS
  #EXE_FILE = global_enkf

  are commented out.

5) make clean; make