Project: Developing a quasigeostrophic ocean circulation model for irregular domains
Supervisors: Prof Pavel Berloff
Project Description:
The present state-of-art of the ocean general circulation modelling involves a hierarchy of models. On the top level there are climate-type global Earth system models that have heavily parameterised, and, therefore, very badly represented, primitive-equations oceans, because of the necessity to balance all the global complexity involved. On the next level there are so-called “eddy-resolving” ocean models, which are very expensive, both computationally and in terms of the involved output data analyses. The above types of models need specialised research institutions and long-term investments to deal with them. On the next level there are so-called “intermediate-complexity” models, such as multi-layer shallow-water dynamics in simple configurations and its asymptotic quasigeostrophic (QG) incarnation. There are thousands of papers published with the QG approach, proving that it is one of the great theoretical successes, aiming at reproducing realistically physical processes, without capturing many details.
The main problem with QG models is that they are configured to work only in simple rectangular domains, such as double-periodic or closed rectangles, or straight channels, because of the involved direct elliptic-problem solvers that use Fourier transforms. Here, the use of indirect (iterative) elliptic solvers, more adaptable for general domains, is ruled out, because they require too many iterations to converge to an acceptable level of numerical accuracy.
The main objective is to transform the QG modelling landscape and push it to the next level of physical complexity. More specifically, the idea is to upgrade and test in various settings the existing and well-respected QG (oceanic and atmospheric) model code “PEQUOD”. This particular numerical model is algorithmically the most efficient one out of the existing QG models and is widely used (in simple domains). The end goal will be to do realistic coastline for QG-type conceptual and process studies, and develop a QG model of the Mediterranean Sea, with all its complicated coastlines.
