The Surface Ocean Carbon Atlas (SOCAT) is a community effort to assemble and quality control all publically available surface water partial pressure/fugacity of carbon dioxide CO2 data (pCO2 or fCO2). This data is the cornerstone to determine fluxes of CO2 between the ocean and atmosphere, and trends in surface ocean acidification.
SOCAT version 3 was released on 7 September 2015 during the Surface Ocean CO2 Atlas and Surface Ocean pCO2 Mapping Intercomparison (SOCAT-SOCOM) community event preceding the SOLAS Open Science Conference in Kiel, Germany. The Surface Ocean CO2 Atlas (SOCAT) is an activity by the international marine carbon research community. It improves access to, and use of, surface water CO2 data by regular releases of quality controlled and documented, fCO2 data products for the global oceans and coastal seas. SOCAT data products enable detection of changes in the ocean carbon sink.
Decadal distribution of quality controlled surface water fCO2 observations in SOCAT version 3. (created with the LAS cruise data viewer www.socat.info)
SOCAT version 3 contains 14.5 million fCO2 data from 3630 data sets for global oceans and coastal seas. The decadal distribution of data is shown on the figure below. This release for the first time includes calibrated sensor data from moorings and floats. The effort includes significant contributions from NOAA/OAR/CPO. Over one-third of the data originates from CPO/COD funded efforts on ship of opportunity (SOOP-CO2) and moorings. Scientists at PMEL and AOML lead and participated in the extensive quality control process. The life access server (LAS), data viewer, user-friendly data and meta data ingester, and automation procedures were lead by the data management group at PMEL with funding from the COD CO2 data management and synthesis proposal.
The SOCAT website provides access to all version 3 products and tools as downloadable files and interactive data viewers.
SOCAT impact and scientific findings
SOCAT represents a milestone in research coordination, data access, biogeochemical and climate research and in informing policy. Investigators and managers at over 140 government agencies, 600 universities and research institutes, and 25 media outlets have accessed the data site: www.socat.info. SOCAT data has been used in more than 100 peer-reviewed scientific publications since the release of version 1 in 2011. Subject areas include year-to-year variability in the global ocean carbon sink, magnitude of carbon sink in coastal and marginal seas, evaluation of CMIP models and ocean acidification research. SOCAT also informs the annual Global Carbon Budget. The data product was the cornerstone of the recent finding that the Southern Ocean CO2 sink has reinvigorated after a period of stagnation (Landshützer et al. Science, 2015).
An offshoot of this SOCAT effort is the Surface Ocean pCO2 Mapping Intercomparison (SOCOM) initiative which is a comparison of data-based air-sea CO2 flux estimates. Fourteen independent methods are applied for interpolating CO2 data from SOCAT in time and space to determine sea-air CO2 fluxes. Approaches include interpolation, (multi-) linear regression, application of a neural network and biogeochemical process modeling. The methods have different characteristics, making them suitable for mapping different space- and time scales. The SOCOM initiative aims to identify common features in the mapping outcomes by different methods. The current comparison of 14 novel approaches includes 3 methods developed by NOAA and CI scientists at AOML, ESRL, and GFDL (Rödenbeck et al. BGD, 2015).
Landschützer, P., Gruber, N., Haumann, F.A., Rödenbeck, C., Bakker, D.C.E., van Heuven, S., Hoppema, M., Metzl, N., Sweeney, C., Takahashi, T., Tilbrook, B., Wanninkhof, R.:The reinvigoration of the Southern Ocean carbon sink. Science 349, 1221-1224, 2015.
Rödenbeck, C., Bakker, D. C. E., Gruber, N., Iida, Y., Jacobson, A. R., Jones, S., Landschützer, P., Metzl, N., Nakaoka, S., Olsen, A., Park, G.-H., Peylin, P., Rodgers, K. B., Sasse, T. P., Schuster, U., Shutler, J. D., Valsala, V., Wanninkhof, R., and Zeng, J.: Data-based estimates of the ocean carbon sink variability – first results of the Surface Ocean pCO2 Mapping intercomparison (SOCOM), Biogeosciences Discuss., 12, 14049-14104, doi:10.5194/bgd-12-14049-2015, 2015.