New master project available

Background:

The North Atlantic thermohaline circulation (THC) – including the circulation and storage of carbon – is completed in the Arctic Mediterranean. Warm and saline Atlantic inflow is transformed by cooling and freshwater input into an outflow of cold and relatively fresh water in the surface and a cold and dense overflow at depth. Each of these tree branches of THC is associated with a different total (and anthropogenic) carbon concentration that in the present climate accommodates a net uptake and export of carbon from the region and into the deep Atlantic Ocean, important for sustaining the ocean CO₂ sink.

Eldevik and Nilsen (2013) recently published a relatively simple framework for making closed and quantitative inference on the strength and structure of the northern THC in response to observed or hypothesized change in heat and/or freshwater budgets. In parallel, Jeansson et al. (2012) constrained a state-of-the-art carbon budget for the Nordic Seas based on observations. These two Bjerknes efforts were originally synchronized to the extent that the former framework originally was used to illustrate and constrain the range of variability of the latter (cf. Figure). This part was eventually removed from Jeansson et al. (2012) as the framework was unpublished by the paper’s acceptance.

We thus have the competence, the specific methodology and data sources, and a first combined and documented analysis at hand to quantify the variability of the northern carbon budget related to ocean circulation, thus directly constraining the carbon storage, uptake and export (total and anthropogenic) of the Nordic Seas, and its variability, an important goal of the Bjerknes Centre. The result will be a more Arctic- and Nordic Seas-focused – but also more well-constrained in terms of THC structure – version of the recent North Atlantic assessment of Pérez et al (2013).

Objective:

to constrain the Arctic Ocean/Nordic Seas carbon budget – total and anthropogenic – based on state-of-the-art carbon observations and a closed and consistent framework for quantifying the co-variability of the advective pathways

Outcomes:

1) master thesis; 2) a GRL-type paper; 3) integration of recent Bjerknes Centre advances in biogeochemistry and climate dynamics

Please contact:

tor.eldevik@gfi.uib.no,  are.olsen@gfi.uib.no  or emil.jeansson@uni.no

References:

Eldevik, T. and J.E.Ø. Nilsen, 2013: The Arctic–Atlantic thermohaline circulation. Journal of Climate, 26, 8690–8705.

Jeansson, E., A. Olsen, T. Eldevik, I. Skjelvan, A.M. Omar, S. Lauvset, J.E.Ø Nilsen, R.G.J. Bellerby, T. Johannessen, and E. Falck, 2011: The Nordic Seas carbon budget: Sources, sinks and uncertainties. Global Biogeochemical Cycles, 25, GB4010.

Pérez, F.F, H. Mercier, M. Vásquez-Rodríguez, P. Lherminier, A. Velo, Paulo C. Pardo, G. Rosón, and A.F. Ríos, 2013: Atlantic Ocean CO₂ uptake reduced by weakening of the meridional overturning circulation. Nature Geoscience, 6, 146–152.