Active subglacial lakes and channelized water flow beneath the Kamb Ice Stream
We identify two previously unknown subglacial lakes beneath the stagnated trunk of the Kamb Ice Stream (KIS). Rapid fill-drain hydrologic events over several months are inferred from surface height changes measured by CryoSat-2 altimetry and indicate that the lakes are probably connected by a subgla...
Main Authors: | , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-12-01
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Series: | The Cryosphere |
Online Access: | http://www.the-cryosphere.net/10/2971/2016/tc-10-2971-2016.pdf |
Summary: | We identify two previously unknown subglacial lakes beneath the
stagnated trunk of the Kamb Ice Stream (KIS). Rapid fill-drain hydrologic
events over several months are inferred from surface height changes measured
by CryoSat-2 altimetry and indicate that the lakes are probably connected by
a subglacial drainage network, whose structure is inferred from the regional
hydraulic potential and probably links the lakes. The sequential fill-drain behavior of the subglacial lakes and
concurrent rapid thinning in a channel-like topographic feature near the
grounding line implies that the subglacial water repeatedly flows from the
region above the trunk to the KIS grounding line and out beneath the Ross Ice
Shelf. Ice shelf elevation near the hypothesized outlet is observed to
decrease slowly during the study period. Our finding supports a previously
published conceptual model of the KIS shutdown stemming from a transition
from distributed flow to well-drained channelized flow of subglacial water.
However, a water-piracy hypothesis in which the KIS subglacial water system
is being starved by drainage in adjacent ice streams is also supported by the
fact that the degree of KIS trunk subglacial lake activity is relatively
weaker than those of the upstream lakes. |
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ISSN: | 1994-0416 1994-0424 |