Decadal evolution of oceanic sink for anthropogenic carbon from 1994 to 2014
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Date
2022-03-03Type
- Other Conference Item
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Abstract
Surface flux estimates and models indicate that the oceanic sink for anthropogenic CO2 (Cant) keeps pace with the increase in atmospheric CO2. However, the latest estimate of the accumulation of Cant in the ocean interior by Gruber et al. (2019) extends only to 2007, preventing an independent assessment. Here, we exploit ~100,000 additional dissolved inorganic carbon and other biogeochemical observations from the quality-controlled data product GLODAPv2.2021, to extend the previous analysis to the 2010s. We refine the eMLR(C*) method that was used by Gruber et al. (2019) in three ways: (1) introduction of objective data cleaning, gap filling and rarefaction procedures, (2) increase in the robustness of the multiple linear regression models through a more stringent predictor and model selection, and (3) enhanced quality of the mapping of the Cant fields by relying on an ensemble approach that considers biases of the method identified through testing with synthetic data generated from an ocean biogeochemical model. Preliminary results confirm that globally the ocean continued to accumulate Cant after 2007, with an average uptake rate of 3.2 ± 0.3 PgC yr-1 for the decade from 2004 through 2014. This is slightly higher than the uptake rate of 2.6 ± 0.3 PgC yr-1 previously determined for the 1994 through 2007 period, which is consistent with the expected increase of the rate based on the growth of atmospheric CO2. On a basin scale, the Atlantic Ocean reveals a steady Cant accumulation across both decades. In contrast, our preliminary results suggest that the Cant accumulation in the Pacific Ocean increased in the second decade, while it might have decreased in the Indian Ocean. Zooming into regional scales, we find that biases associated with the eMLR(C*) method on decadal time scales can mask anomalous changes in the storage rate of Cant. This calls for a continued sampling effort in order to identify changing storage patterns on longer time scales. Show more
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publishedPages / Article No.
Publisher
Ocean Sciences Meeting 2022Event
Organisational unit
03731 - Gruber, Nicolas / Gruber, Nicolas
Notes
Conference lecture held on March 3, 2022.More
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