Downscaling / Upscaling of Ocean Circulation models in the Atlantic

The research will be focused on Downscaling / Upscaling of Ocean Circulation models in the Atlantic. Downscaling has been a huge step forward for the dissemination and increased uptake of the Copernicus Marine Environment Monitoring Service (CMEMS). Downscaling significantly improves the global solution at a local level with higher resolution bathymetries, atmospheric forcing, and river discharges, as well as enhanced quality assurance (QA) through better validation based on local data and assessment by local stakeholders. The research will focus on improved local solution upscaling by assimilating it into the regional solution and then into the global solution to progressively achieve better results in subsequent downscaling.

AIR Centre PhD grants are aimed at applicants enrolled or that comply with the requirements to enrol for PhD related studies and who wish to carry out research towards this degree. Candidates holding a master’s degree or a 5-year undergraduate diploma in Environmental Engineering or related fields may apply. Good skills on Fluid Mechanics (from oceanography or engineering) and programming are preferred. Candidates must explain in the motivation letter their vision of the problem to be solved and why they have the skills necessary to carry the job.

Working Hypothesis
Ocean circulation is the basic stage in the study of the oceans, and its knowledge is essential to all branches of oceanography. Its study is supported by in-situ and remote observation and by mathematical modelling. The in-situ observation allowed the description of the global ocean currents, which were fundamental for navigation for centuries, but the detail of this circulation was only mapped with the advent of remote detection, supported by information technologies that also support modelling. The combination of these three tools is the basis of Operational Oceanography fundamental to the blue economy. In Operational Oceanography modelling is fundamental to forecast ocean circulation and the fate of contaminants of anthropogenic origin, but modelling is still an essential contribution to study physical processes determining ocean circulation and biogeochemistry, where non-linear process enhance the interaction between ocean scales. Smaller spatial and temporal scales controlled by the interaction of local morphological features with larger scale circulation have been addressed downscaling Ocean Global Circulation Model (OGCM) solutions. The implementation of a modelling system initiated through the implementation of a OGCM, the subsequent downscaling process until reaching the local solution, and the assimilation of data to minimize the consequences of boundary condition inaccuracy corresponds to the state of the art of Operational Oceanography. In this process the OGCM models are operated by organizations with global objectives (e.g. Copernicus or HYCOM). Organizations with regional or local interest force their own models using those global model results.

The hypothesis for this thesis is that upscaling of local solutions in a regional solution and that regional solution in the global model contributes to improve those solutions just like the assimilation of observational data does. The use of bidirectional sub models is the classical way of upscaling, but it has two limitations: (1) it must be done in run time and (2) it must be done using the same modelling code for both scale simulations. On the contrary, the use of assimilation techniques identical to those used to assimilate observational data into models permits assimilation to be done offline and results of different models to be assimilated in the same model. The penalty is that models must simulate the same period more than once, as meteorological models do, and a collaborative network must be implemented.

The AIR Centre network can be basic ecosystem hosting an upscaling process. An example of a working flow would be: (1) A model for a large part of the Atlantic is nested into Copernicus model, (2) a regional model is nested into this model and then (3) a local model is nested into this model. A classical downscaling process is used in this process. Then the inverse operation is done using an upscaling process where results of higher resolution models are successively assimilated in lower resolution models.

The work should start with a prototype based on a local and a regional model application based on two different models (MOHID and ROMS) to guarantee independence of codes. Then a simulation for south or north (or both) Atlantic basins should be implemented and other institutions associated to the AIR Centre should be involved. The student should give them support on the downscaling process and they would make their results available to be upscaled to the Atlantic basin model.

Name(s) of supervisor(s)
Supervisor – Ramiro Neves, MARETEC/Instituto Superior Técnico
Co-supervisor – Luiz Paulo Assad, LAMCE/ Federal University of Rio de Janeiro

Name(s) of hosting institution(s)
The work will be carried in the MARETEC Research at Instituto Superior Técnico in the MOHID Modelling team under the supervision of the team coordinator, Prof. Ramiro Neves. At LAMCE, the co-supervisor will support the link with local stakeholders and will support the candidate on the implementation of the ROMS model for the large scale. To reach these objectives, the student can spend part of the time at UFRJ.
The candidate will also cooperate with other institutions associated to the AIR Centre network, promoting downscale where it is not yet done, to increase subsequent upscaling potential.

Identification of PhD program
PhD Program in Environmental Engineering offered by Instituto Superior Técnico.

Please check PhD program’s website for application deadlines here.

Jury Composition
José Alberto Santos Victor (Chairman), Instituto Superior Técnico, Portugal
Nuno Lourenço, CoLAB + Atlântico, Portugal
Marcos Mateus, Instituto Superior Técnico, Portugal

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