# AGU 2021 TALK: PROCESS-BASED MODELING OF GLACIAL TILL ADVECTION
Below is my recorded talk for the [1]American Geophysical Union 2021 Fall
Meeting. Full abstract:
Title: Process-based modeling of glacial till advection
Anders Damsgaard(1), Jan A. Piotrowski(1), Ian Madden(2), Jenny Suckale(2),
Kenny K. Sørensen(3)
1: Department of Geoscience, Aarhus University, Denmark
2: Department of Geophysics, Stanford University, CA, USA
3: Department of Civil and Architectural Engineering, Aarhus University,
Denmark
Glacial flow can reshape the Earth surface through erosion and deposition.
Many past and present ice sheets lie on soft beds, and till mobilization
and transport is governed by the degree of basal coupling, fluctuations in
thermal state, subglacial hydrology, and the mechanics of the basal till
itself. Changes in basal topography due to ice movement could theoretically
feed back onto ice-flow dynamics. For example, the buildup of sedimentary
grounding-zone wedges at the marine termini of ice streams may stabilize
their position against local sea-level change. However, modeling of
subglacial till advection has previously relied on fluid-like rheologies,
which contrasts the now established concensus of Mohr-Coulomb plasticity.
In our work, we aim to improve the parameterization of till advection by
glacial flow. We compare a new continuum model for till against laboratory
consolidation and ring-shear experiments. We show how transient dynamics in
porosity and strength affect the mechanics under non-steady forcings, such
as glacier stick-slip or surge. We couple the till continuum model to an
ice-stream model, and demonstrate how till transport varies when ice flows
over simple soft-bed basal geometries, and affects ice-stream sensitivity
to external forcings.
Slides and video:
- slides:
gopher://adamsgaard.dk/9/npub/agu2021-damsgaard.pdf
- video:
https://adamsgaard.dk/video/agu2021-damsgaard.mp4
References:
[1]
https://www.agu.org/Fall-Meeting
