PhD Studentship A variable North Atlantic sink for anthropogenic CO2: Modelling Observed Change

NERC

We are inviting applications for this joint NERC-Met Office funded PhD studentship to commence between September 2013 and September 2014. The successful applicant will be based within Geography (Streatham Campus, Exeter) at the College of Life and Environmental Sciences, University of Exeter, but with regular access to the Met Office Hadley Centre.

Supervisors:

Dr Paul Halloran: p.halloran@exeter.ac.uk

Professor Andrew Watson: andrew.watson@exeter.ac.uk

Dr Doug McNeall doug.mcneall@metoffice.gov.uk (Met Office Hadley Centre)

Dr Ute Schuster: u.schuster@exeter.ac.uk

The current rise in atmospheric carbon dioxide (CO₂) levels due to fossil fuel burning would be much faster were it not for both the terrestrial and ocean CO₂ sinks. Together these sinks absorb about 50% of anthropogenic CO₂ the emissions (Denman et al., 2007). The ocean sink is the long-term sink, and the North Atlantic and Southern Ocean are the most intense marine region of uptake. These sinks have however been shown to be highly variable (Watson et al., 2009). It is critical that we understand what causes the variability in these CO₂ sinks if we are to understand how they may respond to future anthropogenic CO₂ release and climate change – and therefore how much of the CO₂ released by human activity will remain in the atmosphere, and how much will be taken up by the oceans.

It has been proposed that the observed variability in North Atlantic CO₂ uptake is driven by the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO) (Thomas et al. 2008; McKinley et al., 2011). However, the regular and routine observational air-sea CO₂ flux record spans less than one full cycle of the NAO’s, and less than half a cycle of the AMO’s multi-decadal variability, and therefore our confidence in these relationships remains limited. If links to climate variability are to provide a model for considering the future response of the ocean carbon cycle, we must be confident that the relationships are robust, and understand the mechanisms behind them.

The Research

It has been proposed that the variability in the North Atlantic sink is tied to climate patterns such as the North Atlantic and Atlantic Meridional Oscillations (NAO and AMO) (Thomas et al., 2008; McKinley et al., 2011). You will initially work with state-of-the-art climate-model output produced for the next Intergovernmental Panel on Climate Change (IPCC) assessment, and observations collected over the past two decades. Within the model simulations you will explore the relationship between NAO and AMO variability and CO₂ uptake, then compare the modelled CO₂ fluxes with observational fluxes – some of which you will help collecting by participating in a North Atlantic research voyage. You will explore the mechanisms behind this variability using both simple and state-of-the-art carbon cycle – climate models (e.g Voelker et al., 2000; Collins et al., 2011; Halloran 2012). The aim will be to achieve fundamental understanding of the processes involved in variable carbon uptake, and hence a better idea of how the uptake may change in the future. You will build on recent work which proposes an anthropogenic driver of this variability (Booth et al., 2012), and explore whether human activity has already brought about rapid change the strength of the North Atlantic CO₂ sink.

For more details see the apply button below.

Closing date: midnight 12 November 2013.