mkensemble:
   This routine will create perturbations of the  hycom layer
   thickness using spatial fields with prescribed correlation
   in the horizontal and vertical. Correlation lengths are in
   layers (vertical) and grid cells (horizontal).

   Start file  (member 1), correlation scales and standard 
   deviation of perturbations are specified in the input file
   mkensemble.in. An example of this file is found in the 
   Input directory.

   If a ICE file is found, this will be perturbed as well, but 
   this time by perturbing the ice thickness fields. (In the 
   same way, if a field "hicem" is found in the hycom restart file,
   then this field will be perturbed)