Linear stability theory of equatorial currents will be extended to include wave radiation and vertical mixing. Modal stability analyses of the equatorial current system will be performed using accurate representations of the mean state, including radiation boundary conditions and parameterizations of vertical mixing. The extended theory and analyses will be used to examine both Rossby and Yanai type tropical instability waves. Theoretical results will be synthesized with data from satellite altimetry, TAO moorings, and microstructure profiling.
The project has the potential to impact our understanding of climate by refining or changing our understanding of an important oceanic feature. The project will revisit classical linear theory to incorporate effects that can account for radiation and mixing of energy. While the focus of many studies of tropical instabilities is often to analyze complex circulation models, the proposed work promises to shed light on the fundamental processes that govern the stability of equatorial currents and their subsequent effects on ocean structure and dynamics. In addition, the results could help to settle long standing questions over the stability of equatorial currents - namely where they obtain their energy and how they manifest. In addition to the scientific broader impacts, the study will support the training of a graduate student.
