Southern Ocean's circulation impact on the marine carbon cycle ...

• Main Authors: Menviel, Laurie, Spence, Paul
• Format: Dataset
• Language: English
• Published: Dryad 2023
• Subjects: FOS Earth and related environmental sciences; Carbon; Ocean circulation; southern hemisphere westerlies; Antarctic; Southern Ocean; Antarc*
• Online Access: https://dx.doi.org/10.5061/dryad.mpg4f4r61; https://datadryad.org/stash/dataset/doi:10.5061/dryad.mpg4f4r61

In the context of past and present climate change, the Southern Ocean (SO) has been identified as a crucial region modulating the concentration of atmospheric CO2. The sustained upwelling of carbon-rich deep waters and inefficient nutrient utilisation at the surface of SO leads to an outgassing of natural CO2, while anthropogenic CO2 is entrained to depth during the formation of Antarctic Bottom water (AABW), Antarctic intermediate water (AAIW) and sub-Antarctic mode water (SAMW). Changes to the SO circulation resulting from both dynamic and buoyancy forcing can alter the rate of upwelling as well as formation and subsequent transport of AABW, AAIW and SAMW, thus impacting the air-sea CO2 exchange in SO. Models of all complexity robustly show that stronger southern hemispheric (SH) westerlies enhance the SO upwelling, thus leading to stronger natural CO2 outgassing, with a sensitivity of ∼0.13 GtC/yr for a 10% increase in SH westerly windstress. While the impact of changes in the position of the SH westerly ... : This data present the outputs of several numerical experiments: global eddy-rich model (ACCESS-OM2-01, 0.1deg resolution, 75 vertical levels) forced by the 55-year Japanese Reanalysis for driving oceans (JRA55-do) (Tsujino et al., 2018) over the period 1958 to 2021. global model (ACCESS-OM2, 1deg resolution, 50 vertical levels) forced by the 55-year Japanese Reanalysis for driving oceans (JRA55-do) (Tsujino et al., 2018) over the period 1958 to 2021. sensitivity experiments performed with the (ACCESS-OM2-01, 0.25deg resolution, 50 vertical levels) in which the SH near surface wind speeds are abruptly modified. The zonally uniform and temporally steady perturbations are applied to the CORE-NYF 6-hourly wind field between 25S and 70S with smoothing within 5 degree latitude of the perturbation boundaries. The perturbations include i) a 20% increase, ii) a 20% increase, iii) 4 degree poleward shift, iv) a 16% decrease in windstress between 32S and 65S, and iv) a 4 degree equatorward shift of the SH westerly ...