High-resolution ocean simulations using the NEMO ocean model and AGRIF nesting software

High-resolution numerical ocean modelling requires immense computational power. While ocean models can provide useful results using lower resolutions, there are aspects which can be underrepresented, such as eddies, boundary... [ view full abstract ]

High-resolution numerical ocean modelling requires immense computational power. While ocean models can provide useful results using lower resolutions, there are aspects which can be underrepresented, such as eddies, boundary currents, and areas of rapid change in bathymetry. There are a few ways to produce high-resolution ocean simulations, one of which involves the placement of a high-resolution “nest” inside of a low-resolution configuration. While numerically challenging, it computationally much cheaper than a regular high-resolution simulation.
We used the NEMO (Nucleus for European Modelling of the Ocean) framework to simulate a ¼ degree regional resolution simulation over the northern Atlantic, with a high-resolution nesting package, AGRIF, to achieve our goal of high resolution (1/12 degree) in our region of interest. The numerical code, written in FORTRAN, was well adapted to run on Westgrid’s clusters. We learned that using AGRIF to implement nests allowed for a reduction of computing expense upwards of 90%, when compared with a similar regional configuration using 1/12 degree resolution. The reduction of expense has allowed, and will continue to allow, our lab group to perform additional simulations, addressing more research questions, while using less computing power. We will present current and future-planned simulations using AGRIF to achieve high resolution, addressing research goals, as well as computing expenses associated with each simulation.