Stationary Rossby waves dominate subduction of anthropogenic carbon in the Southern Ocean

The Southern Ocean has taken up more than 40% of the total anthropogenic carbon (C ant ) stored in the oceans since the preindustrial era, mainly in subantarctic mode and intermediate waters (SAMW-AAIW). However, the physical mechanisms responsible for the transfer of C ant into the ocean interior r...

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Bibliographic Details
Published in:Scientific Reports
Main Authors: Langlais, CE, Lenton, A, Matear, R, Monselesan, D, Legresy, B, Cougnon, E, Rintoul, S
Format: Article in Journal/Newspaper
Language:English
Published: Nature Publishing Group 2017
Subjects:
Earth Sciences
Oceanography
Physical Oceanography
Antarctic
Southern Ocean
The Antarctic
Pacific
Indian
Antarc*
Online Access:https://doi.org/10.1038/s41598-017-17292-3
http://www.ncbi.nlm.nih.gov/pubmed/29213120
http://ecite.utas.edu.au/123642
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Summary:The Southern Ocean has taken up more than 40% of the total anthropogenic carbon (C ant ) stored in the oceans since the preindustrial era, mainly in subantarctic mode and intermediate waters (SAMW-AAIW). However, the physical mechanisms responsible for the transfer of C ant into the ocean interior remain poorly understood. Here, we use high resolution (1/10) ocean simulations to investigate these mechanisms at the SAMW-AAIW subduction hotspots. Mesoscale Stationary Rossby Waves (SRWs), generated where the Antarctic Circumpolar Current interacts with topography, make the dominant contribution to the C ant transfer in SAMW-AAIW in the Indian and Pacific sectors (66% and 95% respectively). Eddy-resolving simulations reproduce the observed C ant sequestration in these layers, while lower spatial resolution models, that do not reproduce SRWs, underestimate the inventory of C ant in these layers by 40% and overestimate the storage in denser layers. A key implication is that climate model simulations, that lack sufficient resolution to represent sequestration by SRWs, are therefore likely to overestimate the residence time of C ant in the ocean, with implications for simulated rates of climate change.

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