Ocean Dynamics Impacting Shelf Sea Level in Eastern Atlantic (ODISSEA)

This is a project jointly funded by the National Science Foundation’s Directorate for Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget.

Upon successful joint determination of an award recommendation, each Agency funds the proportion of the budget that supports scientists at institutions in their respective countries.

Global mean sea level is rising due to the combined effects of melting land ice and ocean thermal expansion. Regionally however, sea level is also strongly influenced by changes in the strength and the pathways of large-scale ocean currents, and the long-term trend is often masked by large-amplitude changes over several years. Quantifying and predicting regional patterns are crucial for coastal communities where the magnitude and frequency of extreme sea level events are of immediate societal relevance.

At the U.S. East Coast, sea level rise and variability patterns have been linked to the Atlantic meridional overturning circulation (AMOC). On the NW European shelf, however, comparatively little is known about the impact of AMOC on sea level change, variability, and extremes.

This project will combine direct observations and numerical modeling to better understand the drivers of coastal sea level change on a range of timescales. Such understanding is vital for protecting coastal populations, ecosystems, infrastructure, and maritime industries. The high level of interest in future sea level change, together with the strategic focus of ODISSEA on knowledge and data gaps ensures that the project will have significant impact in the sea level research community.

New knowledge learned from this project will be disseminated to the relevant academic communities (via high-impact ocean and climate journals and at leading international conferences) and local Florida panhandle community in which sea level rise is a keen interest (through education programs and outreach activities at COAPS/FSU). The project will also support the training and career development for a post-doc at FSU to gain experience in the analysis of both observations and model outputs.

This project includes efforts to 1) establish the causal links between deep ocean circulation and shelf sea level changes on monthly to decadal time scales; 2) provide estimates of coastal sea level change for the western UK and Ireland over the next 30-years, with an improved understanding of where and why these changes will occur; and 3) isolate the impact of observed and projected AMOC changes on regional sea level change, variability, and extremes. A key barrier to quantifying and predicting regional patterns of sea level change is understanding the ocean dynamics over the continental slope – the interface between the deep ocean and the shallow continental shelf.

Currents directed from the deep ocean towards the slope may either continue onto the shelf or feed into the rapid along-slope boundary current which encircles the NW European shelf. Further, the large-scale ocean currents are predicted to change with the warming climate, with the AMOC being projected to weaken dramatically in the next 30-years. However, the climate models which yield these predictions lack the fine-scale resolution required to capture the effect of these changes on shelf sea level at a regional scale, in particular the role of narrow boundary currents in modulating the influence of the deep ocean circulation at the coast.

The use of direct observations and high-resolution models will allow this project to quantify and understand the open ocean circulation, how they change over time, and how they impact the coastal sea level change.

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.