Organization: Department of Commerce (DOC)

Research Title: Ocean-Atmosphere Carbon Exchange Study

Funding Level (millions of dollars):

FY94	3.0
FY95	2.6
FY96	2.4

Committee on Environment and Natural Resources (CENR) Component:
(a) Subcommittee: Global Change Research Subcommittee (100%)
(b) Environmental Issue: Climate Change (100%)
(c) Research Activity: System structure and function: Understanding (100%)

Organizational Component:
Office of Global Programs
NOAA/OGP
1100 Wayne Ave., Suite 1225
Silver Spring, MD 20910
Phone/Fax: 301 427-2073

Point of Contact:
James F. Todd
Phone: 301 427-2089
E-Mail: todd@ogp.noaa.gov

Research Goals:
To improve the understanding of the ocean's role in sequestering the increasing global burden of atmospheric carbon dioxide (CO ₂), a major greenhouse gas.

Research Description:
The Ocean-Atmosphere Carbon Exchange Study (OACES) of NOAA's Climate and Global Change (C&GC) Program has two major scientific objectives. The first is to carry out high- quality measurements of carbon dioxide (CO ₂) system parameters that can be used to document the transient invasion of fossil fuel derived CO ₂ into the ocean's interior. The second is to utilize these observations in ocean and atmosphere general circulation models to enable more accurate predictions of future climate change on decadal to centennial timescales. In support of these objectives, the OACES program has been making carbon system measurements on deep ocean survey cruises as well as time-series measurements of atmospheric l2CO ₂ and 13CO ₂ at NOAA's global cooperative flask sampling network sites.

Program Interfaces:
The OACES program addresses research relevant to the goals of the U.S. Joint Global Ocean Flux Study (U.S. JGOFS), a core activity of the International Geosphere- Biosphere Programme (IGBP). OACES research is also relevant to activities of the International Global Atmospheric Chemistry (IGAC) program, also of IGBP. The IGAC program includes global measurements and modeling of atmospheric CO ₂ and its isotopic composition. With respect to NASA, the oceanic measurements made along meridional ocean sections and process study cruises supported by OACES will provide valuable information to the NASA SeaWIFS Ocean Color Satellite mission, namely in situ ocean data that can be used to validate information derived from the satellite (i.e., "ground-truthing"). Another partner in the quest to understand the global carbon cycle is the U.S. Department of Energy (DOE). In addition to supporting CO ₂ measurements on World Ocean Circulation Experiment (WOCE) cruises, DOE is providing certified seawater reference materials to investigators to ensure the analytical quality control of seawater total CO ₂ measurements.

Program Milestones:
Spring, 1994: Complete south Pacific WOCE long-line cruise P18 between 67° S, 103° W and Cabo San Lucas (23° N, 110° W) for carbon system and transient tracer measurements; Spring, 1995: Initiate Arabian Sea/Indian Ocean study (in collaboration with both WOCE and U.S. JGOFS programs). The OACES work in the Indian Ocean will consist of two components: 1) underway surface ocean carbon system measurements during the entire campaign and 2) hydrographic sections along 60° E, 80° E and 8° N (in the southern Arabian Sea) which will be performed as part of the WOCE Hydrographic Program (WHP) seasonal repeat transects. Early 1996: Begin Southern Ocean study (in collaboration with both the WOCE and U.S. JGOFS programs) consisting of an intensified hydrographic survey along 170° W from 5° S to 67° S. This section is one of the WHP long lines (PI5S).

Policy Payoffs:
Improved understanding and assessment of global sources and sinks of atmospheric CO ₂ that will provide the scientific underpinning for future environmental policy issues (for example, national and international energy policies and greenhouse gas emissions reduction agreements). Further, it is expected that OACES research findings will be of substantial value in the IPCC Scientific Assessment of Climate Change reporting process.