Data_Sheet_1_Consistency and Challenges in the Ocean Carbon Sink Estimate for the Global Carbon Budget.PDF

• Main Authors: Judith Hauck, Moritz Zeising, Corinne Le Quéré, Nicolas Gruber, Dorothee C. E. Bakker, Laurent Bopp, Thi Tuyet Trang Chau, Özgür Gürses, Tatiana Ilyina, Peter Landschützer, Andrew Lenton, Laure Resplandy, Christian Rödenbeck, Jörg Schwinger, Roland Séférian
• Format: Dataset
• Language: unknown
• Published: 2020
• Subjects: Oceanography; Marine Biology; Marine Geoscience; Biological Oceanography; Chemical Oceanography; Physical Oceanography; Marine Engineering; ocean carbon uptake; anthropogenic CO2; ocean carbon cycle model evaluation; riverine carbon flux; variability of the ocean carbon sink; seasonal cycle; Southern Ocean
• Online Access: https://doi.org/10.3389/fmars.2020.571720.s001; https://figshare.com/articles/dataset/Data_Sheet_1_Consistency_and_Challenges_in_the_Ocean_Carbon_Sink_Estimate_for_the_Global_Carbon_Budget_PDF/13147556

Based on the 2019 assessment of the Global Carbon Project, the ocean took up on average, 2.5 ± 0.6 PgC yr −1 or 23 ± 5% of the total anthropogenic CO 2 emissions over the decade 2009–2018. This sink estimate is based on simulation results from global ocean biogeochemical models (GOBMs) and is compared to data-products based on observations of surface ocean pCO 2 (partial pressure of CO 2 ) accounting for the outgassing of river-derived CO 2 . Here we evaluate the GOBM simulations by comparing the simulated surface ocean pCO 2 to observations. Based on this comparison, the simulations are well-suited for quantifying the global ocean carbon sink on the time-scale of the annual mean and its multi-decadal trend (RMSE <20 μatm), as well as on the time-scale of multi-year variability (RMSE <10 μatm), despite the large model-data mismatch on the seasonal time-scale (RMSE of 20–80 μatm). Biases in GOBMs have a small effect on the global mean ocean sink (0.05 PgC yr −1 ), but need to be addressed to improve the regional budgets and model-data comparison. Accounting for non-mapped areas in the data-products reduces their spread as measured by the standard deviation by a third. There is growing evidence and consistency among methods with regard to the patterns of the multi-year variability of the ocean carbon sink, with a global stagnation in the 1990s and an extra-tropical strengthening in the 2000s. GOBMs and data-products point consistently to a shift from a tropical CO 2 source to a CO 2 sink in recent years. On average, the GOBMs reveal less variations in the sink than the data-based products. Despite the reasonable simulation of surface ocean pCO 2 by the GOBMs, there are discrepancies between the resulting sink estimate from GOBMs and data-products. These discrepancies are within the uncertainty of the river flux adjustment, increase over time, and largely stem from the Southern Ocean. Progress in our understanding of the global ocean carbon sink necessitates significant advancement in modeling and observing ...