Drivers of Coastal Sea Level Change Along the Eastern US

Abstract: Risks associated with coastal sea level changes and extremes affect the densely populated US East Coast. Yet, numerical simulations struggle to adequately predict the patterns and magnitudes of regional and coastal sea level rise. The uncertainty in coastal sea level projections arises from both uncertainty in internal ocean-atmosphere variability and imperfect representation of oceanic and atmospheric processes in models. In this project, we aim to sharpen our understanding of coastal sea level change along the Eastern US on interannual to multi-decadal timescales. We aim to identify how atmospheric and oceanic drivers and their representation in climate models impact coastal sea level projections. The main analysis will be performed using state-of-the-art coupled climate models from NOAA/GFDL of different ocean and atmosphere horizontal resolutions.
Specifically, we aim to 1) Understand the key drivers and mechanisms of large-scale, open ocean, sea level change on multi-decadal; 2) Quantify changes in sea level and associated extremes along the US East Coast (including the Gulf Coast), and identify physical processes responsible for the changes; 3) Elucidate the connection between ocean interior processes and their response on the shelves to enhance our forecasting capabilities of coastal sea level. Our work will help to guide future model developments by providing robust model diagnostics and observation-based metrics from which to assess climate simulations. In addition, this analysis (the first of its kind) in realistic coupled climate models at eddying resolution will allow us to map risks of sea level changes to time-dependent dynamical drivers vs. time-independent geographical (e.g., bathymetry) drivers.
Relevance to NOAA’s long-term goals and CVP call: Our work will enhance our understanding of natural and forced signals of sea level change in the ocean interior and at the coast. By using a suite of state-of-art coupled climate models, together with an in-depth understanding of physical mechanisms, we aim to map risks of future sea level changes along the US East Coast. These goals, results and methodology directly align with NOAA’s long-term goals and CPO program mission, which includes improving “understanding […] and prediction of climate and its impacts”. More specifically, this work, by focusing on oceanic (including the Atlantic Meridional Overturning Circulation) and atmospheric mechanisms leading to coastal sea level change using historical and future model scenarios, addresses both priority areas set for the CVP FY19 call. Ultimately, our work linking ocean interior signals to coastal sea level change will serve both as a benchmark and a tool for assessing and improving decadal prediction systems.