Space and time variability of the Southern Ocean carbon budget. Issue 9 (14th September 2017)

• Record Type: Journal Article
• Authors: Rosso, Isabella; Mazloff, Matthew R.; Verdy, Ariane; Talley, Lynne D.
• Is Part Of: Journal of geophysical research. Volume 122:Issue 9(2017)
• Page Start: 7407
• Page End: 7432
• Publication Date: 2017-09-14
• Subjects: carbon budget -- Southern Ocean -- state estimate; Oceanography -- Periodicals; 551.4605
• DOI: 10.1002/2016JC012646
• Languages: English
• ISSNs: 2169-9275

Abstract

Abstract: The upper ocean dissolved inorganic carbon (DIC) concentration is regulated by advective and diffusive transport divergence, biological processes, freshwater, and air‐sea CO2 fluxes. The relative importance of these mechanisms in the Southern Ocean is uncertain, as year‐round observations in this area have been limited. We use a novel physical‐biogeochemical state estimate of the Southern Ocean to construct a closed DIC budget of the top 650 m and investigate the spatial and temporal variability of the different components of the carbon system. The dominant mechanisms of variability in upper ocean DIC depend on location and time and space scales considered. Advective transport is the most influential mechanism and governs the local DIC budget across the 10 day–5 year timescales analyzed. Diffusive effects are nearly negligible. The large‐scale transport structure is primarily set by upwelling and downwelling, though both the lateral ageostrophic and geostrophic transports are significant. In the Antarctic Circumpolar Current, the carbon budget components are also influenced by the presence of topography and biological hot spots. In the subtropics, evaporation and air‐sea CO2 flux primarily balances the sink due to biological production and advective transport. Finally, in the subpolar region sea ice processes, which change the seawater volume and thus the DIC concentration, compensate the large impact of the advective transport and modulate the timing of biological activity and air‐sea CO2 flux. Key Points: The carbon budget in the Southern Ocean is analyzed using a physical‐biogeochemical state estimate for the years 2008–2012 The dissolved inorganic carbon budget is dominated by variability in the overturning circulation Temporal variability is enhanced near topography and fronts