ORCHESTRA

PhD studentship available

As part of the NERC-funded INSPIRE Doctoral Training Partnership (https://www.inspire-dtp.ac.uk/), we are seeking applicants for a competition-funded PhD studentship entitled: “The changing freshwater composition of the South Atlantic and Southern Ocean: causes and impacts“. This is a joint project between the British Antarctic Survey (in Cambridge) and the University of Southampton, with supervisors Povl Abrahamsen (BAS), Alberto Naveira Garabato (UoS), Mike Meredith (BAS), Robert Mulvaney (BAS), and Alex Brearley (BAS).

You can find more information about the project at: https://www.findaphd.com/phds/project/the-changing-freshwater-composition-of-the-south-atlantic-and-southern-ocean-causes-and-impacts/?p123752. Links to eligibility criteria and how to apply can be found at: https://www.inspire-dtp.ac.uk/how-apply. The deadline for applications is 4th January 2021, with interviews in the second half of February. The project will commence in late September 2021.

Please see the following brief project description:

The Southern Ocean exerts a disproportionate influence on our planet’s climate, via the strong drawdown of anthropogenic carbon and heat from the atmosphere that occurs there. This role is intimately connected to the Southern Ocean circulation; it is the key region globally where old waters are upwelled to the surface, and new waters created that sink back into the ocean interior. Freshwater inputs to the ocean can impact this circulation, by affecting density gradients and the stability of the upper ocean. Both sea ice meltwater and the melt of Antarctic glaciers exert such an influence, and both are known to be strongly variable, both in time and space. This project will use a tracer of freshwater inputs – the stable isotopes of oxygen in seawater – from the South Atlantic sector of the Southern Ocean to distinguish sea ice melt from other sources of freshwater in historical and recent ocean datasets. By linking these measurements with conventional oceanographic data, satellite data and the outputs of computer simulations, the student will determine the impact of known freshwater inputs on oceanographic circulation, the level to which variability in these sources impacts the ocean, and how such changes might influence climatically-important processes into the future.

When measured alongside salinity, the ratio of stable isotopes of oxygen in seawater is a key tracer for quantifying the input of sea ice melt separately from freshwater from other sources (glacial melt, precipitation). Substantial datasets of oxygen isotopes now exist, with many obtained recently from the NERC-funded ORCHESTRA programme (Ocean Regulation of Climate via Heat and Carbon Sequestration and Transport; https://www.orchestra.ac.uk). Ocean freshwater composition will be derived from these datasets using mass balance techniques, along with quantitative estimates of ocean circulation from inverse techniques applied to conventional oceanographic data, building on, and complementing, the inverse modelling that is being performed as part of ORCHESTRA. This will enable the ocean transports of different freshwater types to be determined, and their changes over time to be quantified. The availability of new datasets will enable these analyses to take place over larger spatial scales (i.e. basin scale) than has been done before. Relating these results to remotely-sensed quantifications of sea ice change and glacial ice change on Antarctica will reveal the impact on the ocean of the different freshwater inputs.

Please note that international students are eligible to apply; a limited number of studentships can be made available to international students. However, as things currently stand, the funding for these studentships will not cover the difference between UK and overseas tuition fees, leaving a shortfall of roughly £20k per year over the course of the 3.5-year PhD (~£70k in total). If you are not a UK citizen or permanent resident, you will need a plan for how you will cover these fees, e.g. through other grant sources. It is also possible that this situation might change before the start of the studentships, but this is not confirmed at present.

Other projects related to ocean/environment/climate are available from the INSPIRE Doctoral Training Partnership and details can be found at: https://noc.ac.uk/gsnocs/projects/inspire

Antarctica Week: calling schools and home schoolers!

From Monday 30th November to Friday 4th December, the Antarctica Week Festival 2020 will give students and the public a unique opportunity to listen to those working on the International Thwaites Glacier Collaboration talk about what it’s like to live and work in Antarctica. Two talks daily from Monday 30th November to Friday 4th December celebrate Antarctica Day – designated to when the Antarctic Treaty was ratified on 1st December 1959.

The exciting programme of talks is below. Please register and if you have a question you would like answered about a specific talk, submit it during registration. The speakers will try to answer them live! The talks are 30 minutes, followed by 30 minutes of questions and answers.

Don’t worry if the times don’t work for your location? We will record all talks and post them on the ITGC website. Any questions about the webinars? Please email us at antarcticaweek@bas.ac.uk

To view the full details and to register for Antarctica Week talks, visit: https://thwaitesglacier.org/news/antarctica-week-festival-2020

ORCHESTRA WP2 meeting report

On the 4th of March the ORCHESTRA WP2 meeting was held at BAS. WP2 focuses on the processes that exchange heat between the ocean mixed layer and interior. Despite travel restrictions on many participants there was an active group of online listeners and speakers from ORCHESTRA and beyond, and a very productive meeting was held, hosted by WP2 lead Dave Munday aided by Andrew Meijers and Alex Brearley. The meeting focused on updates from the various observations, modelling and model analysis groups, as well as planning on how best to synthesize results together into cross disciplinary papers. Additionally ideas for the one year ORCHESTRA extension were scoped out.

Highlights included the showcasing of the regional z and sigma-z models developed at BAS and NOC, demonstrating that the control runs of the z-level model are completed and several perturbation runs are either completed or being run. Encouraging new results from the sigma-z model indicate that a version with fully realised ice shelves and cavities is now working, and producing dense water more ‘realistically’ than the equivalent z level model.

The coming ARCHER downtime will represent a challenge, but also an opportunity to consolidate work to date and get results published.

A slew of adjoint modelling papers looking at Southern Ocean heat uptake sensitivies have been published or in review from Dan Jones and Emma Boland. These models also are providing the basis for perturbation experiments in both ECCO and high resolution model setups to explore heat uptake dynamics.

Pat Hyder of the Met Office showed recent work demonstrating that care needs to be applied when interpreting the results of forced ocean experiments, notably in cases looking at surface heat transports under buoyancy forcing perturbation experiments.

Yavor Kostov gave a guest talk from TICTOC, demonstrating how historical SO SST trends are influenced by both the SAM and GHG forcing variability, but that variability in these processes still struggles to explain the modelled SST warming vs observed cooling.

Andrew Meijers showcased initial CMIP6 water mass heat uptake results, showing that while they largely agree with CMIP5, there is reduced sensitivities of AABW in the newer models.

Alex Brearley, Ryan Scott and Louise Biddle (Gothenburg) updated the group on the initial results from glider and EM-APEX based process studies. These are showing promising results, particularly mixed layer microstructure features and clear resolution of frontal/regional MLD deepening events at high temporal and spatial resolution. Discussion revolved around how to disentangle temporal/spatial features and how to compare these results with more traditional climatology scale analysis of MLD evolution.

Rachael Sanders, despite fighting off a bad illness gave a (remote!) presentation on her mixed layer budget work, showing that surface forcing, lateral advection and mixed layer entrainment dominates the mixed layer heat and freshwater budgets in the SAMW formation regions. Her ongoing work will be to investigate in ECCO how regional wind and buoyancy forcing impact water mass formation rates.

Webinar – SO-CHIC: Southern Ocean Carbon and Heat Impact on Climate

The EPB will host the first in a series of webinars for the project Southern Ocean Carbon and Heat Impact on Climate (SO-CHIC) on 15:00 CEST, Tuesday 7th April 2020. This first webinar, given by project coordinator Jean-Baptiste Sallée from Sorbonne Université, will introduce SO-CHIC and its objectives.

The Southern Ocean regulates the global climate by controlling heat and carbon exchanges between the atmosphere and the ocean. Rates of climate change on decadal time scales ultimately depend on oceanic processes taking place in the Southern Ocean, yet too little is known about the underlying processes. Limitations come both from the lack of observations in this extreme environment and its inherent sensitivity to intermittent small-scale processes that are not captured in current Earth system models.

To contribute to reducing uncertainties in climate change predictions, the overall objective of SO-CHIC is to understand and quantify variability of heat and carbon budgets in the Southern Ocean through an investigation of the key processes controlling exchanges between the atmosphere, ocean and sea ice using a combination of observational and modelling approaches.

The SO-CHIC project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N°821001. For more information on SO-CHIC, please visit http://www.sochic-h2020.eu/.

To register for this webinar, please visit https://zoom.us/webinar/register/WN_Zmuk7prXQciogyJlTMgMeg

Physical Oceanographer vacancy

Description

The British Antarctic Survey is inviting applications for an observational physical oceanographer with a track record of interpreting and analysing observational polar oceanographic datasets. The successful candidate will use observational datasets and numerical model output to construct and test a dynamical framework explaining the circulation of the Weddell Gyre and its export of dense water to the global ocean.

Purpose

This is a 36 month position for a suitably qualified postdoctoral researcher and will contribute to two projects funded by the European Commission H2020 programme and Natural Environment Research Council (NERC): SO-CHIC (Southern Ocean Carbon and Heat Impact on Climate) and ORCHESTRA (Ocean regulation of climate by Heat and Carbon sequestration and Transports).

How to apply: Please visit: https://www.bas.ac.uk/jobs/vacancy/physical-oceanographer-2