Southern Ocean carbon-wind stress feedback

• Published in: Climate Dynamics
• Main Authors: Bronselaer, B, Zanna, L, Munday, DR, Lowe, J
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer Berlin Heidelberg 2018
• Subjects: Southern Ocean
• Online Access: https://doi.org/10.1007/s00382-017-4041-y; https://ora.ox.ac.uk/objects/uuid:cb6fc8d7-2f05-4508-bca1-f5c9e81391c5

The Southern Ocean is the largest sink of anthropogenic carbon in the present-day climate. Here, Southern Ocean (Formula presented.) and its dependence on wind forcing are investigated using an equilibrium mixed layer carbon budget. This budget is used to derive an expression for Southern Ocean (Formula presented.) sensitivity to wind stress. Southern Ocean (Formula presented.) is found to vary as the square root of area-mean wind stress, arising from the dominance of vertical mixing over other processes such as lateral Ekman transport. The expression for p\hbox {CO}_{2} is validated using idealised coarse-resolution ocean numerical experiments. Additionally, we show that increased (decreased) stratification through surface warming reduces (increases) the sensitivity of the Southern Ocean (Formula presented.) to wind stress. The scaling is then used to estimate the wind-stress induced changes of atmospheric (Formula presented.) in CMIP5 models using only a handful of parameters. The scaling is further used to model the anthropogenic carbon sink, showing a long-term reversal of the Southern Ocean sink for large wind stress strength.