Modelled subglacial floods and tunnel valleys control the life cycle of transitory ice streams
<p>Ice streams are corridors of fast-flowing ice that control mass transfers from continental ice sheets to oceans. Their flow speeds are known to accelerate and decelerate, their activity can switch on and off, and even their locations can shift entirely. Our analogue physical experiments...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-08-01
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| Series: | The Cryosphere |
| Online Access: | https://www.the-cryosphere.net/12/2759/2018/tc-12-2759-2018.pdf |
| Summary: | <p>Ice streams are corridors of fast-flowing ice that control mass transfers
from continental ice sheets to oceans. Their flow speeds are known to
accelerate and decelerate, their activity can switch on and off, and even
their locations can shift entirely. Our analogue physical experiments reveal
that a life cycle incorporating evolving subglacial meltwater routing and bed
erosion can govern this complex transitory behaviour. The modelled ice
streams switch on and accelerate when subglacial water pockets drain as
marginal outburst floods (basal decoupling). Then they decelerate when the
lubricating water drainage system spontaneously organizes itself into
channels that create tunnel valleys (partial basal recoupling). The ice
streams surge or jump in location when these water drainage systems maintain
low discharge but they ultimately switch off when tunnel valleys have
expanded to develop efficient drainage systems. Beyond reconciling
previously disconnected observations of modern and ancient ice streams into
a single life cycle, the modelling suggests that tunnel valley development
may be crucial in stabilizing portions of ice sheets during periods of
climate change.</p> |
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| ISSN: | 1994-0416 1994-0424 |