Global biogeochemical cycles, 2016-07, Vol.30 (7), p.983-999
2016
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Details
- Autor(en) / Beteiligte
- Titel
- Quantifying the drivers of ocean-atmosphere CO sub(2) fluxes
- Ist Teil von
- Global biogeochemical cycles, 2016-07, Vol.30 (7), p.983-999
- Erscheinungsjahr
- 2016
- Quelle
- Wiley Online Library - AutoHoldings Journals
- Beschreibungen/Notizen
- A mechanistic framework for quantitatively mapping the regional drivers of air-sea CO sub(2) fluxes at a global scale is developed. The framework evaluates the interplay between (1) surface heat and freshwater fluxes that influence the potential saturated carbon concentration, which depends on changes in sea surface temperature, salinity and alkalinity, (2) a residual, disequilibrium flux influenced by upwelling and entrainment of remineralized carbon- and nutrient-rich waters from the ocean interior, as well as rapid subduction of surface waters, (3) carbon uptake and export by biological activity as both soft tissue and carbonate, and (4) the effect on surface carbon concentrations due to freshwater precipitation or evaporation. In a steady state simulation of a coarse-resolution ocean circulation and biogeochemistry model, the sum of the individually determined components is close to the known total flux of the simulation. The leading order balance, identified in different dynamical regimes, is between the CO sub(2) fluxes driven by surface heat fluxes and a combination of biologically driven carbon uptake and disequilibrium-driven carbon outgassing. The framework is still able to reconstruct simulated fluxes when evaluated using monthly averaged data and takes a form that can be applied consistently in models of different complexity and observations of the ocean. In this way, the framework may reveal differences in the balance of drivers acting across an ensemble of climate model simulations or be applied to an analysis and interpretation of the observed, real-world air-sea flux of CO sub(2). Key Points * We have developed a quantitative framework for diagnosing regional drivers of air-sea CO sub(2) fluxes * Components can be evaluated in a model or can be derived from operational data, climatologies, and ocean state estimates * Model CO sub(2) fluxes result from a balance between air-sea heat fluxes, biological activity, and disequilibrium