Seasonal variability of Southern Ocean CO2 Uptake : A ‘Top-down’ Assessment


Seasonal variability of Southern Ocean CO2 Uptake : A ‘Top-down’ Assessment


Project Description


Dr Parv Suntharalingam (UEA Environmental Sciences)

Dr Anna Jones (BAS)

Dr Andrew Manning (UEA)

Prof Corinne Le Quéré (UEA)

Background and approach

The Southern Ocean plays a fundamental role in regulating global climate through uptake of heat and atmospheric carbon-dioxide (CO2), and removes  ~40% of atmospheric CO2 derived from human activity. Previous studies highlighted significant uncertainties in our estimates of this carbon uptake [Le Quéré et al. 2007, Landschutzer et al, 2015]. These CO2 flux estimates are derived from relatively few measurements, with wintertime oceanic data being particularly sparse due to difficult sampling conditions. A recent study, using newly available ocean biogeochemical float data, has suggested smaller wintertime CO2 uptake than previously believed, and questions our current understanding of the governing processes [Gray et al. 2018].

Air-sea fluxes of CO2 can also be estimated by ‘top-down’ inverse methods which combine atmospheric CO2 measurements with numerical model analyses [Suntharalingam et al. 2005]. The British Antarctic Survey (BAS) and other international agencies have been sampling atmospheric CO2 at sites in and around Antarctica. These atmospheric measurements are made year-round and provide valuable information on oceanic CO2 uptake in the Southern Ocean winter.  In this project you will use these atmospheric measurements together with inverse analysis methods to estimate air-sea fluxes over the Southern Ocean, with a focus on accurately characterising their seasonal variation.

Training and opportunities

The project builds on collaborations between UEA and BAS on the measurement and modelling of CO2 and other greenhouse gases.  At UEA you will work in Dr Suntharalingam’s  biogeochemistry modelling group and with the carbon cycle measurement and modelling groups of Dr Manning and Prof Le Quéré.  At BAS you will work in Dr Jones’  atmospheric measurement group. You will be trained in carbon cycle science, numerical modelling and data analysis, and atmospheric trace-gas measurement methods. You will acquire skills in science communication, project management and collaborative research, and will be involved in a project of critical interest to climate science.

Person specification

This project is suited for a candidate with a background in natural sciences, engineering or mathematics, with strong quantitative skills and interests in applying computational methods to a key climate science issue.


  • Le Quéré, C., et al. (2007). Saturation of the Southern Ocean CO2 sink due to recent climate change, Science 316, 1735, doi: 10.1126/science.1136188.
  • Landschutzer,P., et al. (2015). The reinvigoration of the Southern Ocean carbon sink. Science 349, 6253, pp. 1221-1224, doi: 10.1126/science.aab2620.
  • Gray, A., et al. (2018). Autonomous biogeochemical floats detect significant carbon dioxide outgassing in the high-latitude Southern Ocean, Geophysical Research Letters, doi: 10.1029/2018gl078013
  • Suntharalingam, P., et al. (2005). The influence of reduced carbon emissions and oxidation on the distribution of atmospheric CO2: Implications for inversion analyses, Global Biogeochemical Cycles, 19, 4, doi: 10.1029/2005GB002466.
  • Keeling, R. and A. Manning (2014). Studies of recent Changes in atmospheric O2 content, Treatise on Geochemistry: Second Edition. Vol. 5, p. 385-404.

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