Global Carbon Data Management and Synthesis Project

Principal Investigators: Brendan Carter, NOAA Pacific Environmental Laboratory & Rik Wannikhof, NOAA Atlantic Oceanographic and Metoerological Laboratory

Project Summary

1.1. Project justification
Over the past two and a half centuries, the surface oceans have absorbed approximately 30% of humankind’s carbon dioxide (CO 2 ) emissions (Prentice et al. 2001; Canadell et al. 2007; Le Quéré et al. 2009) . Ocean CO 2 uptake has reduced the accumulation of greenhouse gases in the atmosphere and slowed the rate of climate change (IPCC 2019; Sabine and Feely 2007; Feely et al. 2012; Gruber et al. 2019) . The current consensus measurements-based estimate of ocean uptake for 2008-2017 is 2.5 ± 0.5 Pg C yr -1 . 1 The estimate gets updated annually, in part with data and synthesis products from this project. When anthropogenic CO 2 is absorbed by seawater chemical reactions occur that reduce both seawater pH and the concentration of carbonate ions in a process known as “ocean acidification.” The pH of surface ocean waters has decreased by about 0.11 units since the beginning of the industrial revolution (Jiang et al. 2019) , and it is continuing to decrease at a rate of 0.0021 ± 0.0007 year −1 (e.g., Woosley et al. 2016) . Questions remain regarding the details, mechanisms, feedbacks, and consequences of ocean carbon uptake and acidification. Continued monitoring and scientific analysis of the ocean carbon cycle is critical for understanding how this important sink for anthropogenic CO 2 is functioning; how ocean carbon storage might change in the future; and how we can best anticipate, mitigate, and
adapt to potential future changes.

Carbon data synthesis is essential for monitoring ocean carbon uptake due to the global scale of uptake, the complexities of interpreting ocean carbon measurements, and the variety of ways carbon content is measured. Measurement programs from 15+ participating nations contribute measurements of many different aspects of seawater chemistry made with a wide variety of sensors and analytical techniques. Data from these diverse measurements are ultimately used with Earth system model assessments, data-assimilating models, forecasts, property budgets, and measurement inversions designed to address scientific questions related to ocean carbon uptake. A common element of all of these analyses is that they benefit from consistently-formatted and quality-controlled ocean carbon measurements with well-constrained uncertainties. Data synthesis is therefore necessary to translate the wealth of information provided by the measurement community into the quality controlled and assessed data products needed for advancing and communicating global carbon cycle science.

1.2. Project overview
The global ocean carbon Data Management and Synthesis Project (DMSP) exists to provide resources and leadership to efficiently address the ocean carbon data needs of the global scientific community, decision makers, and the public. DMSP scientists are also charged with conducting original ocean carbon cycle research. DMSP investigator tasks include:

1. measuring ocean carbon;
2. quality controlling ocean carbon data;
3. providing ocean carbon data in common, convenient, and accessible formats;
4. assessing ocean carbon data uncertainty;
5. interpreting ocean carbon data;
6. and communicating relevant findings to decision makers and the broader public.

The DMSP brings together ocean carbon measurement and information technology experts from the Atlantic Oceanographic and Meteorological Laboratory (AOML) and Pacific Marine Environmental Laboratory (PMEL). These scientists work closely with data managers at the National Center of Environmental Information (NCEI) and the CLIVAR and Carbon Hydrographic Data Office (CCHDO) to address the oceanographic community’s carbon data access and synthesis needs. The DMSP prioritizes workup and analysis of data obtained through efforts funded by the Ocean Observations and Monitoring Division (OOMD, soon Global Ocean Monitoring and Observation, or GOMO) including the repeat hydrography program, the partial
pressure of CO 2 (pCO 2 ) on ships of opportunity effort (SOOP-CO 2 ), and the pCO 2 on moorings effort. Appreciable efforts are also made to incorporate data from non-COD investigators worldwide. Investigators in DMSP are leaders in design, automation, and quality control of the
annual Surface Ocean Carbon Atlas release (SOCAT) and are major contributors to an independent surface water pCO 2 data collation performed by the Lamont-Doherty Earth Observatory that serves as a critical check and for climatological analyses. Data synthesis efforts are aimed at addressing the core questions as described in the US Carbon Cycle Science Plan (Michalak et al. 2009) :

1. Where has the anthropogenic carbon (i.e. carbon produced by human activities) entered the ocean? 
2. … and where is it stored?
3. How are these patterns of uptake and storage changing?
4. How is ocean carbon uptake impacting marine inorganic carbon chemistry?

The DMSP aims to quantify global anthropogenic CO 2 storage to within 2 Pg C decade -1 and regional sea-air CO 2 fluxes to within 0.2 Pg C year -1 . The DMSP pursues this goal directly through original research, and indirectly by developing educational programs, methods, datasets, and data products to aid research efforts by the broader scientific community. DMSP scientists engage in additional outreach and educational programs tailored to the broader public with the goal of informing the public of significant advances in understanding the role of the ocean in climate.
Transparency and accessibility are critical for DMSP research, data, and data products. Data and data products are made available online at CCHDO 2 , NCEI 3 , and the AOML/PMEL 4 institutional websites. New data are not currently provided in real-time due to the need for post-measurement
calibration and data quality control and synthesis, but an automated near real-time data reduction and QC program for surface water CO 2 measurements is being pursued. Instead, preliminary data and finalized data are provided following timetables specified by guidelines of the measurement programs. Once submitted, data and data products are continually updated and archived, and efforts have been made to verify these websites are providing up-to-date versions. This has led to significant improvements in delivery time and quality control of the OOMD sponsored underway and repeat hydrography data. Data use statistics are kept by the US Repeat-Hydro and Global Ocean Ship-Based Hydrographic Investigations Programs (GO-SHIP) 5 Acknowledgement of OOMD/NOAA and NSF funding is made on the front page of the CCHDO website. Publications, that include OOMD fund reference #100007298, can be found online for both AOML and PMEL 6 .

1 Global Carbon Budget-2017 see http://www.globalcarbonproject.org/carbonbudget
2 http://cchdo.ucsd.edu/
3 https://www.ncei.noaa.gov/
4 http://www.aoml.noaa.gov/ and http://www.pmel.noaa.gov/