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

• 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

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.