ABSTRACT

Intellectual Merit: The systematic and global re-occupation of select hydrographic sections begun during 2003-2008 will be continued in the 2009-2014 period with the continued objective of quantifying changes in storage and transport of heat, fresh water, carbon dioxide (CO2) and related chemical parameters. The program is in support of CLIVAR (CLImate Variability and predictability) and the Carbon Science Programs, and is a component of a global observing system for the physical climate and carbon system. By integrating the scientific needs of the carbon, tracer and hydrographic communities, major scientific synergies and cost savings will continue to be achieved. In addition to efficiency, the coordinated approach produces scientific advances that exceed those of having individual programs. These advances continue to contribute to the following overlapping scientific objectives: Data for Model Calibration, Validation and Model Based Synthesis; Carbon System Studies; Heat and Freshwater Storage and Flux Studies; Deep and Shallow Water Mass and Ventilation Studies; and Calibration of Autonomous Sensors. A joint study of the ocean carbon cycle and circulation is helping to identify critical areas where potential changes in ocean circulation could have serious consequences for future anthropogenic uptake. Global warming-induced changes in the ocean?s transport of heat and freshwater, which could affect the circulation, are being followed through these long-term measurements. An average of two sections will be conducted every year, sometime collaboratively with international partner. The measurements made on each section include hydrography (full-depth vertical profiles of salinity, temperature, oxygen, nutrients, currents), Underway surface temperature, salinity, partial pressure of carbon dioxide (pCO2), air-sea fluxes, bathymetry, navigation), carbon system (dissolved inorganic carbon, pCO2. Total Alkalinity, pH, dissolved organic carbon and nitrogen), and transient tracers (CFCs, SF6, tritium/3He). This project will collect the data and perform the quality control measures routinely carried out by providers of reference-quality data. Post-cruise data updates, distribution, and archive will continue to be managed by groups with separate funding. This ongoing project is integrated with a larger international effort to monitor the ocean's response to climate change.

Broader Impacts: The results will be disseminated broadly to enhance scientific and technological understanding. The project is based on the fundamental concept that data collected belong to the community, and are available to the community at large rather than being proprietary for the investigators involved in the project. The data policy is stringent and geared towards rapid and open dissemination, with a clear structure for all data to undergo thorough quality control and transmission to a recognized data center. This ambitious degree of openness has resulted in rapid and widespread availability and use of the data. The project benefits to society include the collection of a high quality data set, and use of the data to assess climate change. The global program provides full water column data of climatically significant parameters with decadal coverage. These data are and will be used to assess climate change by quantifying the uptake and storage of anthropogenic CO2 by the ocean, and contributing to an understanding and models of the processes that control the uptake and transport of CO2 into the ocean's interior. Since these are likely to be the only systematic observations below 2000 m, they are and will be used to document long term trends in ocean warming, and heat and freshwater fluxes. The data will remain a resource for model calibration of the climate system. The project will continue to promote training and learning. It will continue to serve as a community resource for training and entraining graduate students, postdoctoral scientists, and new scientists in sea-going work. Outreach activities will continue as opportunities arise.

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