c   To Do:
c   ------
c
c   Selection of forcing fields
c
c      1. Cyclic forcing should be available for each field type
c         (surface forcing and relaxation to climatology).
c
c   Cleaning package
c
c   Many assumptions that are made in the current version should, and
c   can, be relaxed in later versions:
c
c   - equidistancy in time -->  general data set (non-equidistant in
c                                                 time)
c
c   - climatologies        -->  arbitrary subinterval of a year, not
c                               just monthly values.
c
c   - relaxation           -->  relaxation could be done to a given
c                               data set over the model's integration
c                               time. This would generalise the clima-
c                               tology block. One could have 'cyclic'
c                               and 'non-cyclic' fields. In the first
c                               case, the cycle length has to be spe-
c                               cified ('monthly','yearly','period') as
c                               well as the start of the cycle ( irec=1
c                               corresponds to a certain calendar date).
c                               The second case can be treated analog-
c                               ously.
c
c
c   Notes regarding more complete implementation of relaxation
c   ==========================================================
c
c   Modifications in subroutine
c   INITIALISE_FIXED (from c27 on):
c   -------------------------------
c   .
c   .
c   .
c   C--   Set coriolis operators
c         CALL INI_CORI( myThid )
c
c#ifdef INCLUDE_LAT_CIRC_FFT_FILTER_CODE
cC--   Latitude circle filter initialisation
c      CALL FILTER_LATCIRC_FFT_INIT(myThid)
c      _BARRIER
c#endif
c
c   #ifdef INCLUDE_EXTERNAL_FORCING_PACKAGE
c
c         call exf_Init( mythid )
c
c   #ifdef ALLOW_CLIMTEMP_RELAXATION
c   c--   Set the relaxation coefficient to the temperature climatology.
c         call exf_GetTempClimLambda(
c        I                            mythid
c        &                          )
c         _BARRIER
c   #endif
c   #ifdef ALLOW_CLIMSALT_RELAXATION
c   c--   Set the relaxation coefficient to the salinity climatology.
c         call exf_GetSaltClimLambda(
c        I                            mythid
c        &                          )
c         _BARRIER
c   #endif
c   #ifdef ALLOW_CLIMSST_RELAXATION
c   c--   Set the relaxation coefficient to the sst climatology.
c         call exf_GetSSTClimLambda(
c        I                           mythid
c        &                         )
c         _BARRIER
c   #endif
c   #ifdef ALLOW_CLIMSSS_RELAXATION
c   c--   Set the relaxation coefficient to the sss climatology.
c         call exf_GetSSSClimLambda(
c        I                           mythid
c        &                         )
c         _BARRIER
c   #endif
c   #endif
c
c   c--   Finally, summarise the model cofiguration.
c         CALL CONFIG_SUMMARY( myThid )
c   .
c   .
c   .
c
c
c   external_forcing.F  -  Add relaxation to climatological fields.
c
c
c   Modifications in subroutine
c   EXTERNAL_FORCING_T (taken from c25):
c   ------------------------------------
c   .
c   .
c   .
c   #ifdef INCLUDE_EXTERNAL_FORCING_PACKAGE
c   #include "exf_clim.h"
c   #endif
c   .
c   .
c   .
c   C--   Forcing term
c   C     Add heat in top-layer
c         IF ( kLev .EQ. 1 ) THEN
c          DO j=jMin,jMax
c           DO i=iMin,iMax
c            gT(i,j,kLev,bi,bj)=gT(i,j,kLev,bi,bj)
c        &  +maskC(i,j)*(
c        &   -lambdaThetaClimRelax*(theta(i,j,kLev,bi,bj)-SST(i,j,bi,bj))
c        &   -Qnet(i,j,bi,bj)*recip_Cp*recip_rhoNil*recip_dRf(kLev) )
c
c   #ifdef INCLUDE_EXTERNAL_FORCING_PACKAGE
c   #ifdef ALLOW_CLIMSST_RELAXATION
c            gt(i,j,klev,bi,bj) = gt(i,j,klev,bi,bj) -
c        &                        maskc(i,j)*lambda_climsst(i,j,bi,bj)*
c        &                        ( theta(i,j,klev,bi,bj) - 
c        &                          climsst(i,j,bi,bj)     )
c   #endif
c   #endif
c
c           ENDDO
c          ENDDO
c         ENDIF
c
c   #ifdef INCLUDE_EXTERNAL_FORCING_PACKAGE
c   #ifdef ALLOW_CLIMTEMP_RELAXATION
c         do j=jmin,jmax
c          do i=imin,imax
c           gt(i,j,klev,bi,bj) = gt(i,j,klev,bi,bj) -
c        &                       maskc(i,j)*lambda_climtemp(i,j,klev,bi,bj)*
c        &                       ( theta(i,j,klev,bi,bj) - 
c        &                         climtemp(i,j,klev,bi,bj) )
c          enddo
c         enddo
c   #endif
c   #endif
c   .
c   .
c   .
c
c
c   Modifications in subroutine
c   EXTERNAL_FORCING_S (taken from c25):
c   ------------------------------------
c   .
c   .
c   .
c   #ifdef INCLUDE_EXTERNAL_FORCING_PACKAGE
c   #include "exf_clim.h"
c   #endif
c   .
c   .
c   .
c   C--   Forcing term
c   C     Add fresh-water in top-layer
c         IF ( kLev .EQ. 1 ) THEN
c          DO j=jMin,jMax
c           DO i=iMin,iMax
c            gS(i,j,kLev,bi,bj)=gS(i,j,kLev,bi,bj)
c        &   +maskC(i,j)*(
c        &   -lambdaSaltClimRelax*(salt(i,j,kLev,bi,bj)-SSS(i,j,bi,bj))
c   #ifdef ALLOW_NATURAL_BCS
c        &   +EmPmR(i,j,bi,bj)*recip_dRf(1)*salt(i,j,kLev,bi,bj)
c   #else
c        &   +EmPmR(i,j,bi,bj)*recip_dRf(1)*35.
c   #endif
c        &   )
c
c   #ifdef INCLUDE_EXTERNAL_FORCING_PACKAGE
c   #ifdef ALLOW_CLIMSSS_RELAXATION
c            gs(i,j,kLev,bi,bj) = gs(i,j,kLev,bi,bj) -
c        &                        maskc(i,j)*lambda_climsss(i,j,bi,bj)*
c        &                        ( salt(i,j,kLev,bi,bj) - 
c        &                          climsss(i,j,bi,bj)    )
c   #endif
c   #endif
c
c           ENDDO
c          ENDDO
c         ENDIF
c
c   #ifdef INCLUDE_EXTERNAL_FORCING_PACKAGE
c   #ifdef ALLOW_CLIMSALT_RELAXATION
c         do j=jmin,jmax
c          do i=imin,imax
c           gs(i,j,klev,bi,bj) = gs(i,j,klev,bi,bj) -
c        &                       maskc(i,j)*lambda_climsalt(i,j,klev,bi,bj)*
c        &                       ( salt(i,j,klev,bi,bj) - 
c        &                         climsalt(i,j,klev,bi,bj) )
c          enddo
c         enddo
c   #endif
c   #endif
c   .
c   .
c   .