commit dd64f92875f51862c8d7a03c318f0cdd0937b0c7
parent d2be7475df969bb9fc21d7ff4c80b043b7db0c20
Author: Anders Damsgaard <anders@adamsgaard.dk>
Date: Wed, 9 Dec 2020 11:09:29 +0100
add plaintext version of commsenv post for gopher
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+The majority of glaciers and ice sheets flow on a bed of loose and
+thawed sediments. These sediments are weakened by pressurized glacial
+meltwater, and their lubrication accelerates the ice movement. In
+formerly-glaciated areas of the world, for example Northern Europe,
+North America, and in the forelands of the Alps, the landscape is
+reshaped and remolded by past ice moving the sediments along with
+its flow. The sediment movement is also observed under current
+glaciers, both the fast-moving ice streams of the Greenland and
+Antarctic ice sheets, as well as smaller glaciers in the mountainous
+areas of Alaska, northern Sweden, and elsewhere. The movement of
+sediment could be important for the past progression of glaciations,
+and how resilient marine-terminating ice streams are against sea-level
+rise.
+
+Today, the Nature-group journal Communications Earth & Environment
+published my paper on sediment beneath ice. Together with co-authors
+Liran Goren, University of the Negev (Israel), and Jenny Suckale,
+Stanford University (California, USA), we present a new computer
+model that simulates the coupled mechanical behavior of ice, sediment,
+and meltwater. We calibrate the model against real materials, and
+provide a way forward for including sediment transport in ice-flow
+models. We also show that water-pressure variations with the right
+frequency can create create very weak sections inside the bed, and
+this greatly enhances sediment transport. I designed the freely-available
+program cngf-pf for the simulations.
+
+
+## Abstract
+
+ Water pressure fluctuations control variability in sediment
+ flux and slip dynamics beneath glaciers and ice streams
+
+ Rapid ice loss is facilitated by sliding over beds consisting
+ of reworked sediments and erosional products, commonly referred
+ to as till. The dynamic interplay between ice and till reshapes
+ the bed, creating landforms preserved from past glaciations.
+ Leveraging the imprint left by past glaciations as constraints
+ for projecting future deglaciation is hindered by our incomplete
+ understanding of evolving basal slip. Here, we develop a continuum
+ model of water-saturated, cohesive till to quantify the interplay
+ between meltwater percolation and till mobilization that governs
+ changes in the depth of basal slip under fast-moving ice. Our
+ model explains the puzzling variability of observed slip depths
+ by relating localized till deformation to perturbations in
+ pore-water pressure. It demonstrates that variable slip depth
+ is an inherent property of the ice-meltwater-till system, which
+ could help understand why some paleo-landforms like grounding-zone
+ wedges appear to have formed quickly relative to current
+ till-transport rates.
+
+
+## Metrics
+
+It is a substantial task to prepare a scientific publication. The
+commit counts below mark the number of revisions done during
+preparation of this paper:
+
+ - Main article text: 239 commits
+ - Supplementary information text: 35 commits
+ - Experiments and figures: 282 commits
+ - Simulation software: 354 commits
+
+
+## Links and references:
+
+ - Publication on journal webpage:
+ - Article PDF (?? MB):
+ - Supplementary information PDF (?? MB):
+ - Source code for producing figures: git://src.adamsgaard.dk/cngf-pf-exp1
+ - Simulation software: git://src.adamsgaard.dk/cngf-pf
