Intellectual Merit: Our understanding of lateral dispersion in the ocean on scales between 100's of meters and 10's of kilometers has received relatively little attention, despite the fact that lateral dispersion plays an important role in the spatial and temporal distribution of many properties in the ocean. Recent work by the scientists involved in this study has begun to elucidate the physics behind lateral dispersion, but we still lack a quantitative understanding of the relationship between the larger scale field, the internal wave field, and mixing across density surfaces. In this study, scientists from NWRI and U. Mass. Dartmouth, will conduct process-oriented numerical simulations to account for how energy is transferred between different scales of motion. Simulations will extende previous modeling studies of stirring by small-scale geostropic motions to include momentum fluxes associated with the breaking of internal waves, more realistic larger-scale forcing environments such as large-scale shearing and straining by tides or large-scale internal waves, and a number of other factors such as variations in the generation frequency, size and shape of mixed patches. An important goal of this study is the development of parameterizations so that larger-scale models of the ocean can accurately account for these processes without having to resolve them.
Broader Impacts: Lateral dispersion governs a variety of problems including the rates at which nutrients are mixed, the dynamics and spreading of harmful algal blooms or other contaminants, and the recruitment of commercial fish stocks. Thus, this study will improve our ability to understand and predict a variety of scientific problems that affect the quality of our everyday life. In addition, through collaboration with colleagues at UCLA, the parameterizations to be developed in this study will be incorporated into a widely-used regional ocean model. Finally, the study includes several important educational activities including the mentoring of students in a research project and the enrichment of curriculum.
