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CLM-CN

Specifies parameters for CLM-CN 4.0 reactions.

Required Cards:

CLM-CN

Opens the reaction block.

POOLS

Specifies a list of litter and soil organic matter (SOM) pools to be considered as upstream/downstream carbon/nitrogen pools in CLM-CN reactions.

POOLS
  SOM1 12.
  SOM2 12.
  Lit1
  Lit2
/

Note:

• SOM pools listed must be followed by a floating point C/N ratio [g/g] and the SOM pool must be listed as an immobile species in the CHEMISTRY section.

• Litter pools listed do not provide a C/N ratio as it is variable. Two immobile species must be defined for each litter pool where the name of the species is the name of the pool followed by C and N for carbon and nitrogen, respectively (e.g. Lit1 -> Lit1C and Lit1N).

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REACTION

Opens a block that defines a new reaction for decomposition of plant biomass and SOM.

UPSTREAM_POOL <string>

Name of the upstream pool as listed in POOLS.

DOWNSTREAM_POOL <string>

Name of the downstream pool as listed in POOLS.

TURNOVER_TIME <float> <optional string>

The turnover time (e.g. inverse of rate constant) in seconds unless units (e.g. s, min, h, d, w, mo, y) are provided as the optional string.

RATE_CONSTANT <float> <optional string>

The rate constant in 1/s unless units (e.g. 1/s, 1/min, 1/h, 1/d, 1/y) are provided as the optional string.

Note: TURNOVER_TIME and RATE_CONSTANT may not be present at the same time.

RESPIRATION_FRACTION <float>

Defines the fraction of carbon mineralized.

N_INHIBITION <float>

Inhibition constant defines a threshold for nitrogen update. A monod expression is implemented to inhibit nitrogen uptake at concentrations well below N_INHIBITION when nitrogen is a reactant.

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Examples

Immobile species block

IMMOBILE_SPECIES
  N
  C
  SOM1
  SOM2
  SOM3
  SOM4
  Lit1C
  Lit2C
  Lit3C
  Lit1N
  Lit2N
  Lit3N
/

Reaction sandbox block

REACTION_SANDBOX
  CLM-CN
    POOLS
      SOM1 12.d0
      SOM2 12.d0
      SOM3 10.d0
      SOM4 10.d0
      Lit1
      Lit2
      Lit3
    /
    REACTION
      UPSTREAM_POOL Lit1
      DOWNSTREAM_POOL SOM1
      TURNOVER_TIME 20. h
      RESPIRATION_FRACTION 0.39d0
      N_INHIBITION 1.d-10
    /
    REACTION
      UPSTREAM_POOL Lit2
      DOWNSTREAM_POOL SOM2
      TURNOVER_TIME 14. d
      RESPIRATION_FRACTION 0.55
      N_INHIBITION 1.d-10
    /
    REACTION
      UPSTREAM_POOL Lit3
      DOWNSTREAM_POOL SOM3
      TURNOVER_TIME 71. d
      RESPIRATION_FRACTION 0.29d0
      N_INHIBITION 1.d-10
    /
    REACTION
      UPSTREAM_POOL SOM1
      DOWNSTREAM_POOL SOM2
      TURNOVER_TIME 14. d
      RESPIRATION_FRACTION 0.28d0
      N_INHIBITION 1.d-10
    /
    REACTION
      UPSTREAM_POOL SOM2
      DOWNSTREAM_POOL SOM3
      TURNOVER_TIME 71. d
      RESPIRATION_FRACTION 0.46d0
      N_INHIBITION 1.d-10
    /
    REACTION
      UPSTREAM_POOL SOM3
      DOWNSTREAM_POOL SOM4
      TURNOVER_TIME 2. y
      RESPIRATION_FRACTION 0.55d0
      N_INHIBITION 1.d-10
    /
    REACTION
      UPSTREAM_POOL SOM4
      TURNOVER_TIME 27.4 y
      RESPIRATION_FRACTION 1.d0
      N_INHIBITION 1.d-10
    /
  /
/

Species constraint block

CONSTRAINT initial
  ...
  IMMOBILE
    N     1.d-6
    C     1.d-20
    SOM1  1.d-20
    SOM2  1.d-20
    SOM3  1.d-20
    SOM4  1.d-20
    Lit1C 0.1852d-3
    Lit2C 0.4578d-3
    Lit3C 0.2662d-3
    Lit1N 0.00508954d-3
    Lit2N 0.01258096d-3
    Lit3N 0.00731553d-3
  /
/