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Re: solubility pump



Ray,

My understanding is that the answer is #2 and #3.

>2. An initial condition for anthropogenic CO2 uptake simulations.  In this
>case, surface Alk doesn't matter much because the buffer factor is mainly a
>function of pCO2 and temperature.  Alk choice affects DIC, but not
>perturbation
>DIC.
>
>3. An initial condition for radiocarbon simulations.  This follows Bacastow
>and Maier-Reimer (1990), who found simulated D14C using C-12 and C-14
>in an abiotic ocean is the same as in a biotic ocean with all C isotopes.  I
>don't know how critical surface Alk is here.  We suggested doing C-14 this way
>in Boulder.

The rationale for using surface alk, salinity normalized, was to get a
better estimate of the buffer factor.

Also, the phrase 'is the same' in section 3 should read, 'is nearly the
same' as figures 35a and 35b, and 35b and 35c, do differ from each other by
about 10 o/oo or so (judging from the figures). Also, biology does carry
bomb 14C, but again this is a second-order effect which we will consider in
the standard bio-model case.

Basically, the abiotic cases are cheap ways to get most of the right answer
for 12C and 14C  with a steady-state circulation and without running a full
biogeochemistry model. Since we are not doing 13C (why not???) are we not
considering isotope fractionations associated with gas exchange? [Better
would be to do 13C and consider isotope discrimination in chemistry and gas
exchange.]

Cheers,

Ken


<--------------------------->
Ken Caldeira
Climate System Modeling Group
Lawrence Livermore National Laboratory
7000 East Ave., L-103
Livermore CA 94550 USA

tel: (925)  423-4191 (new area code!)
fax: (925)  422-6388
e-mail:  kenc@LLNL.gov