[asa] Subglacial Water System Moving Faster Than Previously Thought

From today's Science Express:

http://www.sciencemag.org/cgi/content/abstract/1136897v1

An Active Subglacial Water System in West Antarctica Mapped from Space *Helen
Amanda Fricker 1*, Ted Scambos 2, Robert Bindschadler 3, Laurie Padman 4 *

1 Scripps Institution of Oceanography, University of California, San Diego,
La Jolla, CA 92093, USA.
2 National Snow and Ice Data Center, University of Colorado, Boulder, CO
80302, USA.
3 NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
4 Earth & Space Research, Corvallis, OR 97333, USA.

* To whom correspondence should be addressed.
Helen Amanda Fricker , E-mail: hafricker@ucsd.edu

Satellite laser altimeter elevation profiles from 2003-2006 collected over
the lower parts of Whillans and Mercer ice streams, West Antarctica, reveal
14 regions of temporally varying elevation which we interpret as the surface
expression of subglacial water movement. Vertical motion and spatial extent
of 2 of the largest regions are confirmed by satellite image differencing. A
major, previously unknown subglacial lake near the grounding line of Whillans
Ice Stream is observed to drain 2.0 km3 of water over ~3 years, while
elsewhere a similar volume of water is being stored subglacially. These
observations reveal a widespread, dynamic subglacial water system which may
exert an important control on ice flow and mass balance.

Fast flowing subglacial ice streams are important indicators of climate
change and will be helpful in improving our predictions of sea level
rise. The author of this paper was quoted by New Scientist as following:

> We didn't realise that the water under these ice streams was moving in
> such large quantities and on such short time scales. We thought these
> changes took place over years and decades, but we are seeing large changes
> over months," says Helen Fricker at the University of California San Diego's
> Scripps Institution of Oceanography in the US, who led the study.
>
>

Uh, oh. Most of the worry was concerning Greenland and it has been generally
assumed that Antarctica would as it has in past deglaciations lag the
Northern Hemisphere. This appears to challenge that assumption.

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Received on Thu, 15 Feb 2007 18:21:31 -0700