Shelf/Open-Ocean Interactions in the South African Region

Oregon State University, Corvallis OR

Investigators

Abstract

This study uses process modeling to investigate the impact of the Agulhas Current on the southern African shelves, the connectivity between the circulations in the Agulhas Bank and the southern Benguela upwelling region, and the sensitivity of these shelf regions to climate related changes of the wind forcing. The central hypothesis is that shelf and deep-ocean interactions are modulated by the transit of Agulhas eddies. The project will advance understanding of the impact of these interactions on the Agulhas Bank and extend it to the Benguela region. Understanding shelf and deep-ocean interactions in the southern African region will contribute to the forecast of the impact of climate change on the regional ecosystems and the potential feedbacks that those ecosystems will have on the changing climate. This project uses process-oriented modeling to characterize the shelf and open-ocean interactions between the Agulhas Current, Agulhas Bank (AB), and Southern Benguela Upwelling Region (SBUR) and to evaluate their sensitivity to climate variability and climate change. The investigators hypothesize that the AC controls the thermohaline structure of the AB and that it is the main driver of the circulation in the outer- and middle-shelf regions. Wind stress forcing controls the circulation in the inner shelf as well as the exchanges between the AB and the SBUR. The project will investigate eddy-driven interactions between the AC and the African continent and their effect on mixing and water mass transformations along the AC path. It is anticipated that climate change will increase the impact of shelf/open ocean interactions on both oceanic realms. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.