012-agu2021.html (2191B)
1 <p> Below is my recorded talk for the <a 2 href="https://www.agu.org/Fall-Meeting">American Geophysical Union 2021 Fall Meeting</a>. 3 Full abstract:</p> 4 5 <blockquote> 6 <b>Title: Process-based modeling of glacial till advection</b> 7 <br><br> 8 Anders Damsgaard(1), Jan A. Piotrowski(1), Ian Madden(2), Jenny Suckale(2), Kenny K. Sørensen(3) 9 <br><br> 10 1: Department of Geoscience, Aarhus University, Denmark 11 <br> 12 2: Department of Geophysics, Stanford University, CA, USA 13 <br> 14 3: Department of Civil and Architectural Engineering, Aarhus University, Denmark 15 <br><br> 16 Glacial flow can reshape the Earth surface through erosion and 17 deposition. Many past and present ice sheets lie on soft beds, and till 18 mobilization and transport is governed by the degree of basal coupling, 19 fluctuations in thermal state, subglacial hydrology, and the mechanics of 20 the basal till itself. Changes in basal topography due to ice movement 21 could theoretically feed back onto ice-flow dynamics. For example, 22 the buildup of sedimentary grounding-zone wedges at the marine termini 23 of ice streams may stabilize their position against local sea-level 24 change. However, modeling of subglacial till advection has previously 25 relied on fluid-like rheologies, which contrasts the now established 26 concensus of Mohr-Coulomb plasticity. 27 <br><br> 28 In our work, we aim to improve the parameterization of till advection by 29 glacial flow. We compare a new continuum model for till against laboratory 30 consolidation and ring-shear experiments. We show how transient dynamics 31 in porosity and strength affect the mechanics under non-steady forcings, 32 such as glacier stick-slip or surge. We couple the till continuum model 33 to an ice-stream model, and demonstrate how till transport varies when 34 ice flows over simple soft-bed basal geometries, and affects ice-stream 35 sensitivity to external forcings.</blockquote> 36 37 38 <p>Slides and video:</p> 39 40 <ul> 41 <li><a href="npub/agu2021-damsgaard.pdf">slides (pdf)</a></li> 42 </ul> 43 44 <center> 45 <video poster="video/agu2021-damsgaard.jpg" 46 controls preload="none" class="mediaframe"> 47 <source src="video/agu2021-damsgaard.mp4" type="video/mp4"> 48 <a href="video/agu2021-damsgaard.mp4">Link</a> 49 </video> 50 </center>