PhD Scholarship in Physical Oceanography Technical University of Denmark

Technical University of Denmark - National Institute of Aquatic Resources (DTU Aqua)

A PhD Scholarship in Physical Oceanography is available at the National Institute of Aquatic Resources (DTU Aqua) with starting date January 2012. The position is part-financed through NAACOS (North Atlantic - Arctic coupling in a changing climate: impacts on ocean circulation, carbon cycling and sea-ice), and through a stipendium DHI Water • Environment • Health (DHI).

The project will primarily be carried out through the Section for Ocean Ecology and Climate which is situated in Charlottenlund, Denmark, and at DHI.

DTU Aqua is an institute at the Technical University of Denmark. The purpose of DTU Aqua is to provide research, advice and education at the highest international level within the sustainable exploitation of living marine and freshwater resources, the biology of aquatic organisms and the development of ecosystems as well as their integration in ecosystem-based management. The institute has an international research staff comprising approx. 90 academic employees.

Project description:
Entrainment processes in the Faroe Bank Channel deep water overflow - ocean modeling and observations.

This project will investigate the physical entrainment processes of the Faroe Bank Channel deep water plume in order to address the corresponding uncertainty in present day ocean climate models. For the Arctic Ocean and Nordic Seas exchange of water masses with the North Atlantic a critical oceanic bottleneck is the flow of dense deep water over the Greenland-Scotland Ridge (GSR). This is a local phenomenon with global implications. Accurate descriptions of these flows are central in predicting future changes in Atlantic meridional overturning circulation. Observations show that the overflow is determined by hydraulic criticality, a feature present-day ocean climate models fail to capture due to their coarse resolution compared to the scale of oceanic eddies and their interactions with steep topography. After crossing the sill at the GSR, the plume transport is almost doubled by entrainment of ambient water. The bulk of the entrainment takes place within only a few hundred kilometers from the sill. With a direct impact on the global thermohaline circulation (THC), a proper representation of these processes in climate models is essential in order to reduce the known uncertainties in projected THC changes and oceanic heat transport towards the Arctic.

The mixing efficiency of oceanic turbulence contributing to the entrainment of deep water overflow plumes is presently inadequately quantified. The project will focus on the mixing efficiency of velocity shear generated turbulence, internal waves, mesoscale eddy stirring and Ekman pumping in such plumes. Special emphasis is on the Faroe Bank Channel and the downstream entrainment region. Using a combination of hydrostatic and non-hydrostatic numerical modeling techniques and exploiting the flexible mesh finite volume solvers of the MIKE by DHI oceanographic model, MIKE 3, a set of models for studying the entrainment processes in the overflow plume will be developed. All models will be calibrated against existing observations and joint analysis of observations and high resolution local scale model results will quantify the relative importance of each physical process responsible contributing to the overall downstream entrainment. This will allow quantification of the uncertainty of existing coarse resolution ocean climate models.

Qualifications
We are looking for a candidate who has:

• M.Sc. or equivalent;
• Good understanding of oceanography, fluid dynamics, stratified flows and turbulence;
• Experience with numerical modeling and process based analysis of in situ data and model results.

Application deadline: 7 November 2011

To view the full announcement and to apply: www.dtu.dk/career