Anthropogenic carbon pathways towards
the North Atlantic interior revealed by Argo-
O2, neural networks and back-calculations
Published in Nature Communications
Feb 2024
The subpolar North Atlantic (SPNA) is a region of high anthropogenic CO2
(Cant) storage per unit area. Although the average Cant distribution is well
documented in this region, the Cant pathways towards the ocean interior
remain largely unresolved. We used observations from three Argo-O2 floats
spanning 2013-2018 within the SPNA, combined with existing neural networks
and back-calculations, to determine the Cant evolution along the float pathways
from a quasi-lagrangian perspective. Our results show that Cant follows a
stepwise deepening along its way through the SPNA. The upper subtropical
waters have a stratified Cant distribution that homogenizes within the winter
mixed layer by Subpolar Mode Water formation in the Iceland Basin. In the
Irminger and Labrador Basins, the high-Cant footprint (> 55 μmol kg−1) ismixed
down to 1400 and 1800 dbar, respectively, by deep winter convection. As a
result, the maximum Cant concentration is diluted (<45 μmol kg−1). Our study
highlights the roleofwater mass transformation as a first-ordermechanism for
Cant penetration into the ocean. It also demonstrates the potential of Argo-O2
observations, combined with existing methods, to obtain reliable Cant estimates,
opening ways to study the oceanic Cant content at high spatio-temporal
resolution.
Citation:
Asselot, R., Carracedo, L.I., Thierry, V. et al. Anthropogenic carbon pathways towards the North Atlantic interior revealed by Argo-O2, neural networks and back-calculations. Nat Commun 15, 1630 (2024). https://doi.org/10.1038/s41467-024-46074-5.
