If you want to use nudging in M2radiation, you use cpps :
East_FSchampman , East_M2Radiation and East_Nudging together.
There is an error that the 'zeta_east' can't be writed !!
this error can be overcomed by adding the following code in globaldefs.h
#ifdef OBC_M2RADIATION
# if defined SOUTH_M2NUDGING
# define SOUTH_FSOBC
# endif
# if defined NORTH_M2NUDGING
# define NORTH_FSOBC
# endif
# if defined EAST_M2NUDGING
# define EAST_FSOBC
# endif
# if defined WEST_M2NUDGING
# define WEST_FSOBC
# endif
#endif