THURSDAY MARCH 14 @ 12P / NOON PDT
Modelling interactions between the solid-Earth, cryosphere, and oceans to better predict future sea-level change
Matthew Hoffman, Los Alamos National Lab
Changes in global mean sea level are caused by changes in ocean mass (changes in water stored in land ice and in terrestrial reservoirs) and ocean density (thermosteric changes). Sea level changes vary around the Earth as changes in surface loading induce solid Earth deformation and perturbations to gravitational equipotentials and the Earth’s axis of rotation. In addition to coastal impacts, these relative sea-level changes impact the larger Earth system by modifying marine ice sheet dynamics, ocean dynamics, and crustal stresses. I’ll be presenting an overview of projects in our group exploring these interactions. By coupling ice-sheet and sea-level models, we demonstrate how the low mantle viscosities of West Antarctica lead to relative sea-level fall regionally and a substantial delay in retreat of marine-based glaciers there, but that this negative feedback to glacier retreat is most effective when climate changes slowly. From here, we explore how changes in relative sea level and ocean bathymetry may impact the access of warm ocean masses to the margins of the ice sheet and its subsequent melting. Looking further afield, we investigate the impact of relative sea level changes on ocean tides and ocean dynamic sea level (local variations in sea surface height caused by ocean dynamics) globally under future climate. Finally, we consider how the perturbations to crustal stress induced by changing ice and water loading on the Earth’s crust may affect earthquake occurrence in the Arctic under present and future climate. The larger goal of these investigations is developing a unified framework for representing sea-level in the Energy Exascale Earth System Model (E3SM) developed by the US Department of Energy.
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