Presenter
Sönke Dangendorf
Assistant Professor, Department of Ocean, Earth and Atmospheric Sciences
Center for Coastal Physical Oceanography
Old Dominion University
Norfolk, VA, USA
Description
Estimating 20th century global and regional sea-level rise and the individual contributors (the so-called sea-level budget) is currently hampered by the sparsity of in-situ observations (e.g. tide gauges, hydrographic profiles) in combination with a complex geometry of the individual contributing processes. In this presentation I will provide insights into some of the key challenges related to the reconstruction of sea-level changes and introduce a probabilistic approach based on a Kalman Smoother (Hay et al., 2015) that assimilates prior information on individual processes and their spatial covariances. The prior information contains (i) an ensemble of independent observational estimates of the 20th century spatial-temporal fingerprints of contemporary barystatic mass changes from glaciers, ice-sheets, and terrestrial water storage, (ii) several state-of-the-art Glacial Isostatic Adjustment models, and (iii) climate model and ocean reanalysis fields of dynamic ocean circulation driven sea-level changes. The inclusion of these priors allows for a separation of individual sea-level budget components and their uncertainties that are constrained by the available tide gauge network. The resulting spatial-temporal fields of sea level are not only important for assessing coastal sea-level budgets at individual locations but also as indicators of unobserved processes such as (nonlinear) vertical land motion.
Reference
Hay, C. C., Morrow, E., Kopp, R. E., & Mitrovica, J. X. (2015). Probabilistic reanalysis of twentieth-century sea-level rise. Nature, 517(7535), 481-484.
