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Results
of an injection simulation in which CO2
was continuously injected off of the coast
of New York at a depth of 3,025 m and a rate
of 0.1 Pg of carbon per year. The total amount
of injected carbon in each column is shown
after 100 simulated years.
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Kenneth
Caldeira, Lawrence Livermore National Laboratory
James K. Bishop, Lawrence Berkeley National Laboratory
Kenneth Coale, Moss Landing Marine Laboratory
Paul Falkowski, Rutgers University
Howard Herzog and Sallie Chisholm, Massachusetts Institute
of Technology
Russ Davis, Scripps Institution of Oceanography
Gerard Nihous, Pacific International Center for High
Technology Research
Research
Objectives
The
research objectives of the DOE Center for Research
on Ocean Carbon Sequestration (DOCS) are (1) to understand
the efficacy and impacts of various strategies proposed
for ocean carbon sequestration; (2) to focus research
of other groups on the key uncertainties and/or deficiencies
in ocean physics and biogeochemical models; and (3)
to develop the best numerical simulations of ocean
carbon sequestration, both with regard to biological
fertilization and direct injection of CO2
into the deep ocean. This will be accomplished by
incorporating the research of other groups into an
improved model of ocean physics and biogeochemistry
for application to the problem of ocean carbon sequestration.
Computational
Approach
For
our ocean physics model, we are making a transition
from the LLNL verion of GFDL's MOM to the LANL POP
model. Some modifications to the POP code will be
made to improve the numerics of handling point sources
with high spatial concentration gradients. We will
use a variety of standard techniques to accelerate
convergence on stationary initial conditions for
our model experiments (e.g., time step splitting).
Because some ocean sequestration strategies involve
point sources, and the numerics of the models assume
relatively small spatial concentration gradients,
we will explore a number of techniques for handling
these large gradients within the model. These techniques
include testing various tracer advection schemes
(e.g., flux corrected transport, the QUICK scheme,
etc.), and using results from a high resolution regional
model (run at MIT) to initialize the global GCM.
Accomplishments
We
have performed the highest resolution simulations
of direct CO2 injection ever performed
on a global scale. Results of simulations of anthropogenic
CO2 uptake in the Southern Ocean were
published in Science magazine. We have also performed
simulations of iron fertilization of the ocean.
Significance
The rapid accumulation of CO2
in the atmosphere could produce adverse environmental
impacts. Therefore, we must understand the options
available to us to slow this accumulation. To meet
this need, DOE has created the DOCS, which is jointly
managed by Lawrence Berkeley and Lawrence Livermore
national laboratories and works in close collaboration
with a variety of researchers in academia and other
institutions. Our research will help provide the
science base needed to understand the effectiveness
and the environmental impacts of various ocean carbon
sequestration strategies.
Publications
K.
Caldeira and P. B. Duffy, "The role of the Southern
Ocean in uptake and storage of anthropogenic carbon
dioxide," Science 287, 620 (2000).
H.
Herzog, K. Caldeira, and E. E. Adams, "Carbon
sequestration via direct injection," in Encyclopedia
of Ocean Sciences, edited by J.
Steele, S. Thorpe, and K. Turekian (Academic Press
Ltd., London, in press).
K.
Caldeira and G. H. Rau, "Accelerating carbonate dissolution
to sequester carbon dioxide in the ocean: Geochemical
implications," Geophys. Res. Lett. 27, 225
(2000).
http://esd.lbl.gov/DOCS
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