LDEO Takahashi Climatology

Over the last several decades, multiple approaches have been developed to measure the impact of the ocean on the global CO2 cycle, including atmospheric inversions (Feng et al. 2019), global atmospheric O2/N2 (Manning & Keeling 2006), 13C measurements (Quay et al. 1992, Tans et al. 1993), ocean inventory approaches (Gruber et al. 2019,  Muller et al. 2023) and the measurement of surface ocean and atmospheric CO2 (Takahashi et al. 1993). All methods work towards the goal of elucidating the net flux of CO2 from the atmosphere into the ocean. These different approaches have multiple advantages and disadvantages depending on the time and spatial scale of interest. Directly measuring surface ocean and atmospheric CO2 levels has the advantage, given sufficient measurements, of deriving spatial and temporal variability over the ocean surface on short temporal and spatial scales.

The late Taro Takahashi was a leader in efforts to characterize air-sea CO2 flux through the design and deployment of fCO2 systems throughout the global oceans, and also his efforts to assemble, evaluate and construct global ocean climatologies from available fCO2 datasets. He provided the first near-global monthly air-sea CO2 flux climatology in Takahashi et al. (1997), based on available surface water partial pressure of CO2 measurements, and continued with multiple updated versions of the ocean fCO2 climatology (Takahashi et al. 2002, 2009, and 2014); all of which have been highly utilized and cited by carbon cycle researchers from around the world.

In 2023, an updated climatological mean distribution of fCO2 and corresponding net sea–air CO2 flux estimate was developed by the group at LDEO in honor of the legacy of Taro Takahashi. This climatology represents the mean of ocean conditions over the last four decades and is unique relative to other statistical, mechanistic and machine learning approaches (e.g. Rödenbeck et al. 2015, LDEO-HPD,  fCO2-Residual) in that it interpolates in time and space using only the available fCO2 data rather than using proxy variables for gap filling.

We provide and document this last iteration of the Takahashi Climatology using a greatly increased dataset (SOCATv2022) and an updated methodology for time normalization. Because of the high concentration of available observations in the last 2 decades, we conclude the climatology has a reference year of 2010 and fluxes are provided using air-sea partial pressure differences and inputs from the SeaFlux product (Fay & Gregor et al. 2021). The previous version of the climatology and additional pCO2 data information remain available on Taro’s website available here.

References

Fay, A. R., Munro, D. R., McKinley, G. A., Pierrot, D., Sutherland, S. C., Sweeney, C., and Wanninkhof, R.: Updated climatological mean delta fCO₂ and net sea–air CO₂ flux over the global open ocean regions, Earth Syst. Sci. Data Discuss. [preprint], https://doi.org/10.5194/essd-2023-429, in review, 2023

Feng, S., Lauvaux, T., Keller, K., Davis, K. J., Rayner, P., Oda, T., and Gurney, K. R.: A road map for improving the treatment of uncertainties in high‐resolution regional carbon flux inverse estimates, Geophysical Research Letters, 46, 13,461–13,469. https://doi.org/10.1029/2019GL082987, 2019.

Gruber, N., Clement, D., Carter, B. R., Feely, R. A., van Heuven, S., Hoppema, M., et al.: The oceanic sink for anthropogenic co2 from 1994 to 2007. Science 363, 1193–1199. doi: 10.1126/science.aau5153, 2019.

Manning, A. C., and Keeling, R. F., Global oceanic and land biotic carbon sinks from the Scripps atmospheric oxygen flask sampling network, Tellus, 58B, pp. 95-116, 2006.

Müller, J. D., Gruber, N., Carter, B., Feely, R., Ishii, M., Lange, N., et al. (2023). Decadal trends in the oceanic storage of anthropogenic carbon from 1994 to 2014. AGU Advances, 4, e2023AV000875. https://doi.org/10.1029/2023AV000875

Quay, P. D., Tilbrook, B., and Wong C. S., Oceanic uptake of fossil fuel CO₂: carbon-13 evidence, Science, 256, pp. 74-79, 1992.

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, 12, 7251–7278, https://doi.org/10.5194/bg-12-7251-2015, 2015. 

Takahashi, T., Sutherland, S.C., Sweeney, C., Poisson, A., Metzl, N., Tilbrook, B., Bates, N., Wanninkhof, R., Feely, R.A., Sabine, C. and Olafsson, J.: Global sea–air CO2 flux based on climatological surface ocean pCO2, and seasonal biological and temperature effects. Deep Sea Research Part II: Topical Studies in Oceanography, 49(9-10), pp.1601-1622, 2002.

Takahashi, T., Sutherland, S.C., Wanninkhof, R., Sweeney, C., Feely, R.A., Chipman, D.W., Hales, B., Friederich, G., Chavez, F., Sabine, C. and Watson, A.: Climatological mean and decadal change in surface ocean pCO2, and net sea–air CO2 flux over the global oceans. Deep Sea Research Part II: Topical Studies in Oceanography, 56(8-10), pp.554-577, http://dx.doi.org/10.1016/j.dsr2.2008.12.009. 2009.

Takahashi, T., S. C. Sutherland, D. W. Chipman, J. G. Goddard, C. Ho, T. Newberger, C. Sweeney, and D. R. Munro: Climatological distributions of pH, pCO2, total CO2, alkalinity, and CaCO3 saturation in the global surface ocean, and temporal changes at selected locations, Mar. Chem., 164, 95–125, doi:10.1016/j.marchem.2014.06.004, 2014.

Tans, P.P., Berry, J.A., Keeling, R.F.: Oceanic 13C/12C observations: a new window on ocean CO2 uptake. Global Biogeochemical Cycles 7.2: 353-368, 1993.