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GOSAC Objective 2

• The relative amount of injected CO2 which remains in the ocean and how that varies with time for 1000-yr simulations at seven different sites (at 2-3 depths/site); and
• The regional distribution of the plume of excess CO2 extending from each of the injection sites as well as related changes in pH, carbonate ion, pCO2, and the air-sea flux of CO2;

1. Work Content

1.1 Methodology

To achieve Objective 2, GOSAC must determine the time scale for eventual loss to the atmosphere of additional CO2 stored in the ocean, which determines the effectiveness of ocean CO2 storage as one means to help mitigate rising levels of atmospheric CO2.

Details of planned simulations:

1. Initial conditions: present day (1990) state (OCMIP natural + OCMIP anthropogenic CO2 runs);
2. Post-1990 fossil emissions: injected into each model's 1-box atmosphere
3. Control run: use GOSAC-IEAGHG emissions scenario (to be determined)
4. Injection runs: use same scenario minus 0.6 GT C/yr in the atmosphere. Simultaneously, 0.7 GT C/yr (total) will be injected into the ocean. The difference, 0.1 GT C/yr is associated with the cost of sequestering CO2 in the ocean
5. Seven sites (to be determined as a fnction of practical and oceanographic considerations);
6. Three depths at each site (e.g., 800, 1500, and 3000 m);
7. Three injection runs; 2 control runs
• Injection runs (simultaneous injection at all 7 sites)
• Run 1: 7 sites at 800 m
• Run 2: 7 sites at 1500 m (as permitted by bathymetry)
• Run 3: 7 sites at 3000 m (as permitted by bathymetry)
• Control Runs
• Run 4: control run (no injection), standard emissions
• Run 5: control run (no injection), standard emissions minus 0.6 GT C/yr
8. Simultaneous injection runs will require that each site have a separate tracer for DIC (total dissolved inorganic carbon) so that both the individual and the total effect of the injected carbon can be identified. A preliminary study by the IEA GHG postdoc, Olivier Aumont, will determine if nonlinearities associated with carbonate chemistry and interaction between plumes) are important. If interactions are substantial, protocols will be modified.
9. Amount: 0.1 GT C/yr will be injected at each site
• This amount of 0.1 GT C/yr is equivalent to CO2 emissions from
• 60 GW worth of coal-fired power plants
• 150 GW worth of gas-fired power plants.
• Note: 0.6 GT C/yr will be subtracted each year relative to emissions to the atmosphere used in the control run. We do not subtract 0.7 GT C/yr (the total for 7 sites x 0.1 GT C/yr) because it requires energy to separate, transport, and pump CO2 to depth. GOSAC-IEAGHG assumes 14% energy penalty, based on removing CO2 from gas-fired plants or advanced technology coal-fired plants.
10. Duration of injection: 100 yr
11. Duration of complete simulation: 1000 yr
12. Analysis: will focus on the gain (injection run minus control) for associated perturbations in atmospheric CO2, air-sea CO2 fluxes, oceanic CO2, and oceanic pH.

1.2 Milestones

GOSAC milestones given below are offered with respect to the reporting dates at 12-month intervals from the beginning of GOSAC.

Year 1:

• Boundary conditions and protocols will have been developed and made available for the deep-ocean CO2 injection runs
• For enhanced CO2 storage simulations, through support of the IEA GHG R&D Programme, plans for site selection will coding will be completed for GOSAC members
• Simulations for all GOSAC members will have begun.

• Simulations will have been made with standard boundary conditions and protocols by each partner for GOSAC runs for anthropogenic CO2 (IPCC future scenarios S450 and S650) deep-ocean CO2 injection
• Base analysis will have begun for deep-ocean CO2 injection and business-as-usual simulations.

• Base analysis will have been completed for simulations of deep-ocean CO2 injection.

1.3 Detailed Calendar

The GOSAC-IEAGHG effort is focused on analysis, which is distinguished as that done by the analysis center IPSL/LSCE (Base analysis) and that adopted by other GOSAC participants late in the project (Extended analysis). Base analysis is further broken down into primary, secondary, and tertiary analysis, according to complexity and dependence on results from previous analysis. Examples of each are provided below.

Target dates given below are offered quarterly from the beginning of GOSAC.

Month 3:

• Protocols and boundary conditions will have been finalized, prepared, and made available to GOSAC-IEAGHG participants;
• IPSL model will have been modified for injections runs;
• PSL model ported to T3E (new Cray massively parallel supercomputer) in order that multiple tracer runs are feasible;
• IPSL's offline biology code (more efficient) will be adapted and tested for CO2 disposal runs.
• IPSL control run will have been completed

• Test control and injection simulations with IPSL model will have been completed (7 sites at one depth, e.g., 1000 m)
• Another seven runs, one at each injection site will have been completed, and nonlinearities investigated relative to (a).
• Primary base analysis will have been made on results from IPSL test simulation (e.g., atmospheric CO2 changes, air-sea CO2 fluxes)

• A second multi-site IPSL run will have been completed with the IPSL model at a second depth (e.g., 2000 m)
• Secondary base analysis on IPSL test run will have been completed (e.g., changes in oceanic CO2 and pH; interactions between plumes; evaluation of inter-site differences).
• Advice concerning the test simulation results will have been distributed to GOSAC participants by e-mail

• All participants should have begun coding for multi-site simulations
• Coding will have also begun in preparation for subsequent archiving and general analysis of results from all models.
• Tertiary base analysis will have been made on IPSL results (including animations of temporal changes and slicing of 3-D arrays).
• First annual report will have been written

• GOSAC IEA GHG Coordinator or postdoc will offer services if one or more participants are having difficultly to implementing CO2 sequestration code
• Coding will continue in preparation for base analysis of general model results
• Final individual IPSL model analysis will be completed

• All participating modeling groups will have sent their output following standard GOSAC protocols to LMCE.
• Archiving of output (using netcdf, the standard GOSAC format) will have begun

• All model output will have been archived for subsequent analysis with the GOSAC analysis package (GAP)
• Primary base analysis will have begun for all models

• Secondary base analysis will have begun for all models
• Second annual report will have been written

• Secondary base analysis will continue for all models
• Tertiary base analysis will have begun for all models

• Tertiary base analysis will continue
• Extended analysis will begin by interested GOSAC-IEAGHG members

• Preparation for presentation of GOSAC-IEAGHG results at final GOSAC Workshop
• Preparation of publications
• Base analysis will be completed

• Final Report will have been written
• Executive Summary will have been written
• Publications will have been submitted describing group results

2. Role of Participants

2.1 Coordination

• Coordinator of GOSAC-IEAGHG, GOSAC-EC and OCMIP

• Will prepare boundary conditions for the standard runs by all GOSAC members.
• Will help plan, execute, and analyze GOSAC simulations for enhanced ocean storage of CO2.
• Will help OCMIP participants, as necessary, to participate in GOSAC-IEAGHG.
• Will help in present results and publications.

3.2 Other Responsibilities

• All GOSAC PI's are members of the GOSAC scientific committee.
• That committee contributes to the planning of simulations and analysis, interpretation of results, and participates is in meetings, reports, and papers.
• GOSAC partners will make GOSAC simulations for CO2 sequestration (Objective 2) according to agreed upon protocols using standard boundary conditions. Results from all simulations will be sent to IPSL/LSCE (via Internet, or by exabyte or DAT tape) in standard format.
• GOSAC partners will attend annual GOSAC Workshops (to coincide with OCMIP workshops) in which results will be reported, discussed and further analyses will be planned).

3.3 Interdependence between tasks

As shown in the timetable, GOSAC-EC simulations for natural CO2 must be completed before GOSAC-EC simulations for industrial-era anthropogenic CO2 (1765-1995) can begin. Output from these industrial era CO2 runs are the starting point for GOSAC CO2 ocean injection and business-as-usual simulations. GOSAC-IEAGHG analysis relies upon receiving model output, in a timely manner, from all GOSAC participants.

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