t007-commsenv.txt - adamsgaard.dk - my academic webpage
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       t007-commsenv.txt (3366B)
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            1 The majority of glaciers and ice sheets flow on a bed of loose and
            2 thawed sediments. These sediments are weakened by pressurized glacial
            3 meltwater, and their lubrication accelerates the ice movement. In
            4 formerly-glaciated areas of the world, for example Northern Europe,
            5 North America, and in the forelands of the Alps, the landscape is
            6 reshaped and remolded by past ice moving the sediments along with
            7 its flow. The sediment movement is also observed under current
            8 glaciers, both the fast-moving ice streams of the Greenland and
            9 Antarctic ice sheets, as well as smaller glaciers in the mountainous
           10 areas of Alaska, northern Sweden, and elsewhere. The movement of
           11 sediment could be important for the past progression of glaciations,
           12 and how resilient marine-terminating ice streams are against sea-level
           13 rise.
           14 
           15 Today, the Nature-group journal Communications Earth & Environment
           16 published my paper on sediment beneath ice. Together with co-authors
           17 Liran Goren, University of the Negev (Israel), and Jenny Suckale,
           18 Stanford University (California, USA), we present a new computer
           19 model that simulates the coupled mechanical behavior of ice, sediment,
           20 and meltwater. We calibrate the model against real materials, and
           21 provide a way forward for including sediment transport in ice-flow
           22 models. We also show that water-pressure variations with the right
           23 frequency can create create very weak sections inside the bed, and
           24 this greatly enhances sediment transport. I designed the freely-available
           25 program cngf-pf for the simulations.
           26 
           27 
           28 ## Abstract
           29 
           30     Water pressure fluctuations control variability in sediment
           31     flux and slip dynamics beneath glaciers and ice streams
           32 
           33     Rapid ice loss is facilitated by sliding over beds consisting
           34     of reworked sediments and erosional products, commonly referred
           35     to as till. The dynamic interplay between ice and till reshapes
           36     the bed, creating landforms preserved from past glaciations.
           37     Leveraging the imprint left by past glaciations as constraints
           38     for projecting future deglaciation is hindered by our incomplete
           39     understanding of evolving basal slip. Here, we develop a continuum
           40     model of water-saturated, cohesive till to quantify the interplay
           41     between meltwater percolation and till mobilization that governs
           42     changes in the depth of basal slip under fast-moving ice. Our
           43     model explains the puzzling variability of observed slip depths
           44     by relating localized till deformation to perturbations in
           45     pore-water pressure. It demonstrates that variable slip depth
           46     is an inherent property of the ice-meltwater-till system, which
           47     could help understand why some paleo-landforms like grounding-zone
           48     wedges appear to have formed quickly relative to current
           49     till-transport rates.
           50 
           51 
           52 ## Metrics
           53 
           54 It is a substantial task to prepare a scientific publication. The
           55 commit counts below mark the number of revisions done during
           56 preparation of this paper:
           57 
           58   - Main article text: 239 commits
           59   - Supplementary information text: 35 commits
           60   - Experiments and figures: 282 commits
           61   - Simulation software: 354 commits
           62 
           63 
           64 ## Links and references:
           65 
           66   - Publication on journal webpage: 
           67   - Article PDF (?? MB): 
           68   - Supplementary information PDF (?? MB): 
           69   - Source code for producing figures: git://src.adamsgaard.dk/cngf-pf-exp1
           70   - Simulation software: git://src.adamsgaard.dk/cngf-pf