About the project
While palaeoclimate records suggest that Mediterranean Overflow Water (MOW) dramatically impacted the Atlantic Meridional Overturning (AMOC) circulation, its role in the modern ocean remains uncertain. In situ observations and numerical models will be used to explore impacts on the AMOC of recent and future changes in MOW properties and circulation.
In today’s ocean, the high salinity of the subpolar North Atlantic enables dense water formation by winter cooling, which feeds the Atlantic Overturning circulation (AMOC). Mediterranean Overflow Water (MOW) supplies salt to the North Atlantic, influencing the basin’s salinity budget and the AMOC.
Indeed, palaeoceanographic records and models show that changes in MOW can lead to changes in the AMOC, including a freshening-driven shutdown and dramatic climate change. As a result of anthropogenic climate change, the Mediterranean Sea is warming and becoming saltier at a much higher rate than the global ocean. The impact of such changes on the properties and fate of MOW and the future of the AMOC are unknown, but we hypothesise that MOW salinity increase could make AMOC resilient to freshening at subpolar latitudes.
In this project, you will test these ideas using novel observations and modelling datasets. Specifically, you will:
- use data from autonomous Argo floats to characterise variability in the properties and distribution of MOW within the North Atlantic over the past 25 years
- quantify the contribution of MOW mixing to the water mass transformations driving the AMOC
- using a suite of numerical models, you will investigate how MOW properties and pathways will change in the coming century, and the impacts for the AMOC
You will also be supervised by organisations other than the University of Southampton, including Prof Simon Josey from National Oceanography Centre.
