OS006-04
Common Era Sea-level Budgets along the U.S. Atlantic Coast
Monday, 7 December 2020: 19:16
Virtual
Jennifer Sue Walker1, Robert E Kopp1,2, Timothy Shaw3, Niamh Cahill4, Nicole Khan5, Donald Charles Barber6, Matthew Brain7, Jennifer L Clear8, David Reide Corbett9 and Benjamin Peter Horton3,10, (1)Rutgers University New Brunswick, Department of Earth and Planetary Sciences, New Brunswick, NJ, United States, (2)Rutgers University New Brunswick, Institute of Earth, Ocean, and Atmospheric Sciences, New Brunswick, NJ, United States, (3)Nanyang Technological University, Earth Observatory of Singapore, Singapore, Singapore, (4)Maynooth University, Department of Mathematics and Statistics, Kildare, Ireland, (5)University of Hong Kong, Department of Earth Sciences, Hong Kong, Hong Kong, (6)Bryn Mawr College, Departments of Geology and Environmental Studies, Bryn Mawr, PA, United States, (7)Durham University, Department of Geography, Durham, United Kingdom, (8)Liverpool Hope University, Department of Geography and Environmental Science, Liverpool, United Kingdom, (9)East Carolina University, Department of Coastal Studies, Greenville, NC, United States, (10)Nanyang Technological University, Asian School of the Environment, Singapore, Singapore
Abstract:
A sea-level budget improves understanding of driving processes of sea-level change through time and the relative contributions of these processes. However, most sea-level budget assessments are focused on global-mean sea level and are limited to the 20th and 21st centuries. For the first time we estimate the sea-level budget on centennial to millennial timescales of the Common Era (last 2000 years). We focus our analysis on the U.S. Atlantic coast to better understand the temporal evolution and variability of driving processes that have determined sea-level changes in the past and present, and which will shape such changes in the future. A thorough understanding of these changes is needed for regional to local planning and response to sea-level rise.
We estimate site-specific sea-level budgets over the Common Era at six sites on the U.S. Atlantic coast. With an updated global database of instrumental and proxy sea-level records coupled with a spatiotemporal empirical hierarchical model, we use the unique spatial scales of driving processes to separate relative sea-level records into global, regional, and local-scale components. We find that each budget is dominated by regional-scale, temporally-linear processes driven by glacial isostatic adjustment through the Common Era. This signal exhibits a spatial gradient, with fastest rates of rise in southern New Jersey (1.6 ± 0.02 mm yr-1). Non-linear regional and local-scale processes, such as ocean/atmosphere dynamics and groundwater withdrawal, are of smaller magnitude and exhibit both temporal and spatial variability, with a contribution between -0.3 and 0.4 mm yr-1. The most significant change to the budgets is the increasing influence of the global signal due to ice melt and thermal expansion since 1800 CE, which reaches a 20th century rate of 1.3 ± 0.1 mm yr-1.
