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INITIALIZATION
DIC_ABIOTIC.h contains the common block for the
parameters and fields needed to calculate the air-sea
flux of  and  . The fixed parameters are set in
dic_abiotic_param which is called from gchem_init_fixed.F.
The parameters needed for the biotic part of the calculations
are initialized in dic_biotic_param and are stored
in DIC_BIOTIC.h. The first guess of pH is calculated
in dic_surfforcing_init.F.
LOADING FIELDS
The air-sea exchange of and need wind, atmospheric
pressure (although the current version has this hardwired to 1),
and sea-ice coverage. The calculation of pH needs silica fields.
These fields are read in in dic_fields_load.F. These
fields are initialized to zero in dic_ini_forcing.F.
The fields for interpolating are in common block in
DIC_LOAD.h.
FORCING
The tracers are advected-diffused in ptracers_integrate.F.
The updated tracers are passed to dic_biotic_forcing.F
where the effects of the air-sea exchange and biological
activity and remineralization are calculated and the tracers
are updated for a second time. Below we discuss the
subroutines called from dic_biotic_forcing.F.
Air-sea exchange of is calculated in dic_surfforcing.
Air-Sea Exchange of depends on T,S and pH. The determination
of pH is done in carbon_chem.F. There are three subroutines
in this file: carbon_coeffs which determines the coefficients
for the carbon chemistry equations; calc_pco2 which calculates
the pH using a Newton-Raphson method; and calc_pco2_approx
which uses the much more efficient method of Follows et al.
The latter is hard-wired into this package, the former is kept
here for completeness.
Biological productivity is determined following
McKinely et al. and is calculated in bio_export.F
The light in each latitude band is calculate in insol.F.
The formation of hard tissue (carbonate) is linked to
the biological productivity and has an effect on the
alkalinity - the flux of carbonate is calculated in
car_flux.F. The flux of phosphate to depth where
it instantly remineralized is calculated in phos_flux.F.
Alkalinity tendency comes from changes to the salinity from
addition/subtraction of freshwater in the surface. This
is handled in alk_surfforcing.F.
Oxygen air-sea exchange is calculated in o2_surfforcing.F.
DIAGNOSTICS
Averages of air-sea exchanges, biological productivity,
carbonate activity and pH are calculated. These are
initialized to zero in dic_biotic_init and
are stored in common block in DIC_BIOTIC.h.
Next: 6.4.3 Do's and Don'ts
Up: 6.4 DIC Package
Previous: 6.4.1 Introduction
Contents
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