A Global Finite Element Model for Glacial Isostatic Adjustment with 3D Non-Linear Viscosity

Glacial isostatic adjustment (GIA) is the phenomenon where the solid Earth responds to ice shelves that grow or shrink. As the weight of an ice shelf on the Earth reduces, the Earth rebounds in that location and gravity increases. This rebound process has an instant component, elastic rebound, but also a delayed component as the mantle material slowly flows to a new equilibrium position with timescale determined by the mantle viscosity. GIA affects both the vertical land motion (VLM) and therefore relative sea level (RSL). When predicting sea-level change in the near-future ice mass and sea level changes need to be monitored. However, measurements of current ice mass change are obscured by uplift and gravity changes due to GIA. With a large portion of the world population and economic activity located in coastal areas it is important to monitor sealevel rise and therefore to understand the GIA contribution to sea level rise itself and measurements of the processes....