\(\newcommand{\p}[1]{\frac{\partial }{\partial #1}}\) \(\newcommand{\pp}[2]{\frac{\partial #1}{\partial #2}}\) \(\newcommand{\dd}[2]{\frac{d #1}{d #2}}\) \(\newcommand{\h}{\frac{1}{2}}\) \(\newcommand{\op}[1]{\operatorname{#1}}\)

8.7.3.10. Dynamic CDOM

To enable dynamic CDOM, define DARWIN_ALLOW_CDOM in DARWIN_OPTIONS.h. Part of the dissolved organic matter produced by grazing and plankton mortality and part of remineralized particulate organic matter then goes into a fixed-stoichiometry CDOM pool. The CDOM tracer is in units of mmol C m-3 if DARWIN_CDOM_UNITS_CARBON is defined and mmol P m-3 otherwise.

If DARWIN_CDOM_UNITS_CARBON is defined:

\[S_{\op{CDOM}} = f_{\op{CDOM}} \left( R_{\op{POC}} + g^{\op{DOC}} + \sum_j M^{\op{DOM}}_j \right) - D_{\op{CDOM}}\]

where \(R_{\op{POC}}\) is remineralization of POC, \(g^{\op{DOC}}\) grazing loss to DOC, \(M^{\op{DOM}}_j\) mortality loss to DOC and

\[D_{\op{CDOM}} = \left( r^{\op{degrad}}_{\op{CDOM}} + r^{\op{bleach}}_{\op{CDOM}} \min(1, I/I_{\op{CDOM}}) \right) f^{{{\text{remin}}}}(T) \cdot \op{CDOM}\]

CDOM degradation that goes into dissolved organic matter pools.

If DARWIN_CDOM_UNITS_CARBON is undefined:

\[S_{\op{CDOM}} = f_{\op{CDOM}} \left( R_{\op{POP}} + g^{\op{DOP}} + \sum_j M^{\op{DOM}}_j Q^{\mathrm{P}}_j \right) - D_{\op{CDOM}}\]

where \(R_{\op{POP}}\) is remineralization of POP, \(g^{\op{DOP}}\) grazing loss to DOP, \(M^{\op{DOM}}_j\) mortality loss to DOC and \(D_{\op{CDOM}}\) is defined as above.

Note that with DARWIN_ALLOW_DENIT defined, CDOM degradation stops when \({\mathrm{O}}_2<{\mathrm{O}}_2^{{\text{crit}}}\) and \(\op{NO}_3<\op{NO}_3^{{\text{crit}}}\) (but bleaching continues), see Section 8.7.3.9.

Table 8.40 Parameters in namelist DARWIN_CDOM_PARAMS

Param

Symbol

Default

Units

Description

fracCDOM

\(f_{\op{CDOM}}\)

2/100

fraction of remineralized POP contributing to CDOM

CDOMdegrd

\(r^{\op{degrad}}_{\op{CDOM}}\)

1/200days

1/s

CDOM degradation rate

CDOMbleach

\(r^{\op{bleach}}_{\op{CDOM}}\)

1/15days

1/s

CDOM bleaching rate

PARCDOM

\(I_{\op{CDOM}}\)

20

μEin/m2/s

PAR where CDOM bleaching becomes maximal

R_NP_CDOM

\(R^{\mathrm{N}:\mathrm{P}}_{\op{CDOM}}\)

16

mmol N / mmol P

CDOM N:P ratio (with #undef DARWIN_CDOM_UNITS_CARBON)

R_FeP_CDOM

\(R^{\mathrm{Fe}:\mathrm{P}}_{\op{CDOM}}\)

1D-3

mmol Fe / mmol P

CDOM Fe:P ratio (with #undef DARWIN_CDOM_UNITS_CARBON)

R_CP_CDOM

\(R^{\mathrm{C}:\mathrm{P}}_{\op{CDOM}}\)

120

mmol C / mmol P

CDOM C:P ratio (with #undef DARWIN_CDOM_UNITS_CARBON)

R_NC_CDOM

\(R^{\mathrm{N}:\mathrm{C}}_{\op{CDOM}}\)

16/120

mmol N / mmol C

CDOM N:C ratio (with #define DARWIN_CDOM_UNITS_CARBON)

R_PC_CDOM

\(R^{\mathrm{P}:\mathrm{C}}_{\op{CDOM}}\)

1/120

mmol P / mmol C

CDOM P:C ratio (with #define DARWIN_CDOM_UNITS_CARBON)

R_FeC_CDOM

\(R^{\mathrm{Fe}:\mathrm{C}}_{\op{CDOM}}\)

1D-3/120

mmol Fe / mmol C

CDOM Fe:C ratio (with #define DARWIN_CDOM_UNITS_CARBON)