[SIO GP Seminars] informal seminar

[Gabi Laske]

Dear Informal Seminar Fan,

please join us tomorrow, Thu, Feb 8, 12:15pm in the
IGPP Munk Conference Room

  for

Helen Amanda Fricker

on

Bubbling beneath the ice streams: subglacial plumbing mapped from space

abstract is attached.

Gabi

Satellite laser altimeter elevation profiles from 2003-2006 collected 
over the lower parts of Whillans and Mercer Ice Streams, West 
Antarctica, reveal several regions of temporally varying elevation 
which we interpret as the surface expression of subglacial water 
movement. The detected motions are astonishing in magnitude,
dynamic nature, and spatial extent.  A major, previously unknown 
subglacial lake is observed to drain over ~3 years, while elsewhere a 
similar volume of water is being stored subglacially. These 
observations reveal a  widespread, active subglacial water system which 
may exert an important control on ice flow and mass balance.  The 
time-scale for subglacial water transport is short compared with other 
known drivers of glacial flow variability.  The rapid variation in 
lubrication conditions provides a mechanism for rapid changes in ice 
stream behaviour.  This surprising new information on subglacial water 
processes is fundamental to our understanding of ice stream dynamics 
and to predicting future Antarctic ice sheet behaviour and sea-level 
contribution.
 
This work has been accepted for Science and is due for publication on 
approximately 23 February.

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