carbon_init.F90

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!SFX_LIC Copyright 1994-2014 CNRS, Meteo-France and Universite Paul Sabatier
!SFX_LIC This is part of the SURFEX software governed by the CeCILL-C licence
!SFX_LIC version 1. See LICENSE, CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt  
!SFX_LIC for details. version 1.
!     #########
      SUBROUTINE carbon_init(KNBIOMASS,KNLITTER, KNLITTLEVS, KNSOILCARB)  
!     #####################
!
!!****  *CARBON_INIT* - routine to initialize soil carbon parameters
!!
!!    PURPOSE
!!    -------
!!
!!**  METHOD
!!    ------
!!
!!    EXTERNAL
!!    --------
!!
!!    IMPLICIT ARGUMENTS
!!    ------------------
!!
!!    REFERENCE
!!    ---------
!!
!!      Gibelin et al. 2008, AFM
!!        Modelling energy and CO2 fluxes with an interactive vegetation land surface model -
!!        Evaluation at high and middle latitudes.
!!
!!    AUTHOR
!!    ------
!!      A.-L. Gibelin           * Meteo-France *
!!
!!    MODIFICATIONS
!!    -------------
!!      Original    15/06/09
!!      B. Decharme   2012    variable must be allocated once by run
!!
!-------------------------------------------------------------------------------
!
!*       0.    DECLARATIONS
!              ------------
!
USE modd_co2v_par,       ONLY : xcn, xlc, xfrac_litter, xtau_litter,  &
                                  xfrac_soilcarb, xtau_soilcarb  
USE modd_surf_par,       ONLY : xundef
!
!
USE yomhook   ,ONLY : lhook,   dr_hook
USE parkind1  ,ONLY : jprb
!
IMPLICIT NONE
!
!*       0.1   Declarations of arguments
!              -------------------------
!
INTEGER,              INTENT(IN)    :: knbiomass           ! number of biomass pools
INTEGER,              INTENT(IN)    :: knlitter            ! number of litter pools
INTEGER,              INTENT(IN)    :: knlittlevs          ! number of litter levels
INTEGER,              INTENT(IN)    :: knsoilcarb          ! number of soil carbon pools
REAL(KIND=JPRB) :: zhook_handle
!
!-------------------------------------------------------------------------------
!
IF (lhook) CALL dr_hook('CARBON_INIT',0,zhook_handle)
!
!*       2.     BIOMASS CONSTANTS
!               -----------------
!
! Biomass Carbon/Nitrogen ratio
xcn(1) = 40.0
xcn(2) = 40.0
xcn(3) = 40.0
xcn(4) = 40.0
xcn(5) = 40.0
xcn(6) = 40.0
!    
! Biomass Lignin/Carbon ratio
xlc(1) = 0.22
xlc(2) = 0.35
xlc(3) = 0.35
xlc(4) = 0.35
xlc(5) = 0.35
xlc(6) = 0.35
!    
! Fraction of biomass pools going into litter pools
xfrac_litter(:,1) = 0.85 - 0.018 * xlc(:) * xcn(:)
xfrac_litter(:,2) = 1. - xfrac_litter(:,1)
!  
!
!*       3.     LITTER CONSTANTS
!               ----------------
!        
! Residence times in litter pools (s)
xtau_litter(1) = 0.066*365.0*86400.0
xtau_litter(2) = 0.245*365.0*86400.0
!  
! Fraction of litter decomposition flux that goes into soil.
! The rest goes into the atmosphere
xfrac_soilcarb(:,:,:) = xundef
! 
! Structural litter: lignin fraction goes into slow pool + respiration,
!                    rest into active pool + respiration.
xfrac_soilcarb(2,1,1) = 0.55
xfrac_soilcarb(2,1,2) = 0.45
xfrac_soilcarb(2,2,1) = 0.70
xfrac_soilcarb(2,2,2) = 0.70
!  
! Metabolic litter: all goes into active pool + respiration,
!                   nothing into slow or passive pool.
xfrac_soilcarb(1,1,1) = 0.45
xfrac_soilcarb(1,1,2) = 0.45
!   
!
!*       4.     SOIL CONSTANTS
!               --------------
!  
! Residence times in carbon pools (s)
xtau_soilcarb(1) = 0.149*365.0*86400.0
xtau_soilcarb(2) = 5.480*365.0*86400.0
xtau_soilcarb(3) = 241.0*365.0*86400.0
!
IF (lhook) CALL dr_hook('CARBON_INIT',1,zhook_handle)
!
END SUBROUTINE carbon_init