# 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