Sigma coordinate pressure gradient errors and the basin problem

Abstract

This work will focus on how the internal pressure gradient errors affect the numerical instability in idealised ocean basins. The nature of the errors will be investigated and discussed. First, in Chapter 1, the ocean model and the underlying equations will be discussed. In Chapter 2, different forms of ocean basins will be studied. Experiments will show how the shapes affect the generation of false geostrophic flow in the basins. The results here will show the better basin to proceed with in the later experiments. Further on, in Chapter 3, the basin's ability to represent real physical phenomena will be tested. External and internal Kelvin waves will be used as a measure of how well the model works. The SESK will be found in Chapter 4, together with new errors. In Chapter 5 the model's sensitivity to the advection scheme will be tested. An overview of the results and ideas for future investigations are given in Chapter 6.