!  Fasham Nitrogen-based Biological Model Parameters.
!
!==============================================================================
!  Copyright (c) 2005 ROMS/TOMS Group, version 3.0                          ===
!========================================================= Hernan G. Arango ===
!                                                                             !
! Input parameters can be entered in ANY order, provided that the parameter   !
! KEYWORD (usually, upper case) is typed correctly followed by "="  or "=="   !
! symbols. Any comment lines are allowed and must begin with an exclamation   !
! mark (!) in column one.  Comments may  appear to the right of a parameter   !
! specification to improve documentation.  All comments will ignored during   !
! reading.  Blank lines are also allowed and ignored. Continuation lines in   !
! a parameter specification are allowed and must be preceded by a backslash   !
! (\).  In some instances, more than one value is required for a parameter.   !
! If fewer values are provided, the  last value  is assigned for the entire   !
! parameter array.  The multiplication symbol (*),  without blank spaces in   !
! between, is allowed for a parameter specification.  For example, in a two   !
! grids nested application:                                                   !
!                                                                             !
!    AKT_BAK == 2*1.0d-6  2*5.0d-6              ! m2/s                        !
!                                                                             !
! indicates that the first two entries of array AKT_BAK,  in fortran column-  !
! major order, will have the same value of "1.0d-6" for grid 1,  whereas the  !
! next two entries will have the same value of "5.0d-6" for grid 2.           !
!                                                                             !
! In multiple levels of nesting and/or multiple connected domains  step-ups,  !
! "Ngrids" entries are expected for some of these parameters.  In such case,  !
! the order of the entries for a parameter is extremely important.  It  must  !
! follow the same order (1:Ngrids) as in the state variable declaration. The  !
! USER may follow the above guidelines for specifying his/her values.  These  !
! parameters are marked by "==" plural symbol after the KEYWORD.              !
!                                                                             !
!==============================================================================
!
! NOTICE: Input parameter units are specified within brakets and default 
! ******  values are specified within braces.
!
! Switch to control the computation of biology within nested and/or multiple
! connected grids.

    Lbiology == T

! Maximum number of iterations to achieve convergence of the nonlinear
! solution.

     BioIter == 1

! Light attenuation due to seawater [1/m], {0.04d0}.

       AttSW == 0.04d0

! Light attenuation by chlorophyll [1/(mg_Chl m2)], {0.02486d0}.

      AttChl == 0.02486d0

! Fraction of shortwave radiation that is photosynthetically active
! (nondimensional), {0.43d0}.

     PARfrac == 0.43d0

! Eppley temperature-limited growth parameter [nondimensional], {1.0d0}

         Vp0 == 1.0d0

! Radiation threshold for nitrification inhibition [Watts/m2], {0.0095d0}.

     I_thNH4 == 0.0095d0

! Half-saturation radiation for nitrification inhibition [Watts/m2], {0.036d0}.

     D_p5NH4 == 0.1d0

! Nitrification rate: oxidation of NH4 to NO3 [1/day], {0.05d0}.
 
      NitriR == 0.2d0

! Inverse half-saturation for phytoplankton NO3 uptake [1/(millimole_N m-3)],
! {2.0d0}.

       K_NO3 == 2.0d0

! Inverse half-saturation for phytoplankton NH4 uptake [1/(millimole_N m-3)],
! {2.0d0}.

       K_NH4 == 2.0d0

! Zooplankton half-saturation constant for ingestion [1/day], {1.0d0}.

       K_Phy == 2.0d0

! Maximum chlorophyll to carbon ratio [mg_Chl/mg_C], {0.0535d0}.

     Chl2C_m == 0.0535d0

! Chlorophyll minimum threshold value [mg_Chl/m3], {0.0d0}.

      ChlMin == 0.001d0

! Phytoplankton Carbon:Nitrogen ratio [mole_C/mole_N] , {6.625d0}.

       PhyCN == 6.625d0

! Phytoplankton, NH4 inhibition parameter [1/(millimole_N)], {1.5d0}.

       PhyIP == 1.5d0

! Phytoplankton, initial slope of P-I curve [mg_C/(mg_Chl Watts m-2 day)],
! {0.025d0}.

       PhyIS == 0.025d0

! Phytoplankton minimum threshold value [millimole_N/m3], {0.0d0}.

      PhyMin == 0.001d0

! Phytoplankton mortality rate [1/day], {0.072d0}.

       PhyMR == 0.15d0

! Zooplankton Nitrogen assimilation efficiency [nondimesnional], {0.75d0}.

     ZooAE_N == 0.75d0

! Zooplankton Basal metabolism [1/day], {0.1d0}.

       ZooBM == 0.1d0

! Zooplankton Carbon:Nitrogen ratio [mole_C/mole_N], {5.0d0}.

       ZooCN == 6.625d0

! Zooplankton specific excretion rate [1/day], {0.1d0}.

       ZooER == 0.1d0

! Zooplankton maximum growth rate [1/day], {0.75d0}.

       ZooGR == 0.6d0

! Zooplankton minimum threshold value [millimole_N/m3], {0.0d0}.

      ZooMin == 0.001d0

! Zooplankton mortality rate [1/day], {0.025d0}.

       ZooMR == 0.025d0

! Large detritus remineralization rate N-fraction [1/day], {0.01d0}.

       LDeRRN == 0.01d0

! Large detritus remineralization rate C-fraction [1/day].

       LDeRRC == 0.01d0

! Coagulation rate: aggregation rate of SDeN + Phy ==> LDeN
! [1/day], {0.005d0}.

       CoagR == 0.01d0

! Small detritus remineralization rate N-fraction [1/day], {0.03d0}.

       SDeRRN == 0.3d0

! Small detritus remineralization rate C-fraction[1/day].

       SDeRRC == 0.3d0

! Vertical sinking velocity for phytoplankton [m/day], {0.1d0}.

        wPhy == 0.1d0

! Vertical sinking velocity for large detritus [m/day],
! {1.0d0}.
               
       wLDet == 5.0d0

! Vertical sinking velocity for small detritus [m/day],
! {0.1d0}.

       wSDet == 0.1d0

! CO2 partial pressure in the air (parts per million by volume),
! {377.0d0}.

     pCO2air == 377.4d0

! Lateral, constant, harmonic/biharmonic horizontal diffusion of biological
! tracer: [1:NBT,Ngrids].

        TNU2 == 12*0.0d0                         ! m2/s
        TNU4 == 12*0.0d0                         ! m4/s

! Vertical mixing coefficients for biological tracers: [1:NBT,Ngrids].

     AKT_BAK == 12*1.0d-6                       ! m2/s

! Nudging/relaxation time scales, inverse scales will be computed
! internally: [1:NBT,Ngrids].

       TNUDG == 12*1.0d0                  ! days

! Logical switches (TRUE/FALSE) to activate writing of biological tracers
! into HISTORY output file: [1:NBT,Ngrids].
! NO3 NH4 Chl Phy Zoo LdeN SdeN LdeC SdeC TIC Talk Ox  

Hout(idTvar) == T T T T T T T T T T T T

! Logical switches (TRUE/FALSE) to activate writing of diagnostics terms
! into diagnostic output file [Ngrids].

Hout(iCOfx) == T                      ! air-sea CO2 flux
Hout(iDNIT) == T                      ! denitrification flux
Hout(ipCO2) == T                      ! CO2 partial pressure
Hout(iO2fx) == T                      ! air-sea O2 flux
Hout(iPPro) == T                      ! primary production
Hout(iNO3u) == T                      ! NO3 uptake

!
!  GLOSSARY:
!  =========
!
!------------------------------------------------------------------------------
! Fasham, Nitrogen-based Biological Model Parameters.
!------------------------------------------------------------------------------
!
!  Lbiology  Switch to control the computation of a particular module within
!              nested and/or multiple connected grids. By default this switch
!              is set to TRUE in "mod_scalars" for all grids.  Ngrids values
!              are expected. The USER has the option, for example, to compute
!              the biology in just one of the nested grids. If so, this switch
!              needs to be consistent with the dimension parameter NBT in
!              "mod_param".  In order to make the model more efficient in
!              memory usage, NBT(:) should be zero in such grids.
!
!  BioIter   Maximum number of iterations to achieve convergence of
!              the nonlinear solution.
!
!  AttSW     Light attenuation do to seawater [1/m].
!
!  AttChl    Light attenuation by chlorophyll [1/(mg_Chl m2)].
!
!  PARfrac   Fraction of shortwave radiation that is photosynthetically
!              active (nondimensional).
!
!  Vp0       Eppley temperature-limited and light-limited growth tuning
!              parameter [nondimensional].
!
!  I_thNH4   Radiation threshold for nitrification inhibition [Watts/m2].
!
!  D_p5HN4   Half-saturation radiation for nitrification inhibition
!              [Watts/m2].
!
!  NitriR    Nitrification rate: oxidation of NH4 to NO3 [day-1].
!
!  K_NO3     Inverse half-saturation for phytoplankton NO3 uptake
!              [1/(millimole_N m-3)].
!
!  K_NH4     Inverse half-saturation for phytoplankton NH4 uptake
!              [1/(millimole_N m-3)].
!
!  K_Phy     Zooplankton half-saturation constant for ingestion [1/day].
!
!  Chl2C_m   Maximum chlorophyll to carbon ratio [mg_Chl/mg_C].
!
!  ChlMin    Chlorophyll mimimum threshold value [mg_Chl/m3].  Set to
!              zero to avoid limiting.
!
!  PhyCN     Phytoplankton Carbon:Nitrogen ratio [mole_C/mole_N].
!
!  PhyIP     Phytoplankton, NH4 inhibition parameter [1/(millimole_N)].
!
!  PhyIS     Phytoplankton, initial slope of P-I curve
!              [(mg_C)/(mg_Chl Watts m-2 day)].
!
!  PhyMin    Phytoplankton mimimum threshold value [millimole_N/m3].
!              Set to zero to avoid limiting.
!
!  PhyMR     Phytoplankton mortality rate [1/day].
!
!  ZooAE_N   Zooplankton Nitrogen assimilation efficiency [nondimensional].
!
!  ZooBM     Basal metabolism of zooplankton [1/day].
!
!  ZooCN     Zooplankton Carbon:Nitrogen ratio [mole_C/mole_N].
!
!  ZooER     Zooplankton specific excretion rate [1/day].
!
!  ZooGR     Zooplankton maximum growth rate [1/day].
!
!  ZooMin    Zooplankton mimimum threshold value [millimole_N/m3].
!              Set to zero to avoid limiting.
!
!  ZooMR     Zooplankton mortality rate [1/day].
!
!  LDeRRN    Large nitrogen detritus remineralization rate [day-1].
!
!  LDeRRC    Large carbon detritus remineralization rate [day-1].
!
!  CoagR     Coagulation rate: aggregation rate of SDeN + Phyt ==> LDeN
!              [day-1].
!
!  SDeRRN    Small nitrogen detritus remineralization rate [day-1].
!
!  SDeRRC    Small carbon detritus remineralization rate [day-1].
!
!  wPhy      Vertical sinking velocity for phytoplankton [m/day].
!
!  wLDet     Vertical sinking velocity for large detritus
!              [m/day].
!
!  wLDet     Vertical sinking velocity for large detritus
!              [m/day].
!
!  pCO2air   CO2 partial pressure in the air (parts per million by volume)
!
!  TNU2      Lateral, Laplacian, constant, mixing coefficient (m2/s) for
!            biological tracer variables; [1:NBT,1:Ngrids] values are
!            expected.  If variable horizontal diffusion is activated, TNU2
!            is the mixing coefficient for the largest grid-cell in the domain.
!
!  TNU4      Lateral, biharmonic, constant, mixing coefficient (m4/s) for
!            biological tracer variables; [1:NBT,1:Ngrids] values are
!            expected.  If variable horizontal diffusion is activated, TNU4
!            is the mixing coefficient for the largest grid-cell in the domain.
!
!  AKT_BAK   Background vertical mixing coefficient (m2/s) for biological
!              tracer variables, [1:NBT,1:Ngrids] values are expected.
!
!  TNUDG     Nudging time scale (days), [1:NBT,1:Ngrids].  Inverse scale will
!              be computed internally.
!
!  Hout      Logical switches (T/F) to write out biological data into output
!              NetCDF files:
!
!            History/Average file, [1:NBT,1:Ngrids] values are expeted:
!
!              Hout(idTvar)     biological traces
!
!            Diagnostics file, [Ngrids] values are expected:
!
!              Hout(iCOfx)      air-sea CO2 flux
!              Hout(iDNIT)      denitrification flux
!              Hout(ipCO2)      CO2 partial pressure
!              Hout(iO2fx)      air-sea O2 flux
!              Hout(iPPro)      primary production
!              Hout(iNO3u)      NO3 uptake
