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Radar Reveals Meltwaters Year-Round Life Under Greenland Ice
http://www.ldeo.columbia.edu/news-events/new-study-reveals-meltwaters-year-round-life-under-greenlands-ice[font face=Serif][font size=5]Radar Reveals Meltwater’s Year-Round Life Under Greenland Ice[/font]
January 5, 2017
[font size=4]Exploring Where Liquid Goes, Even in Winter[/font]
[font size=3]When summer temperatures rise in Greenland and the melt season begins, water pools on the surface, and sometimes disappears down holes in the ice. That water may eventually reach bedrock, creating a slipperier, faster slide for glaciers. But where does it go once it gets there, and what happens to it in the winter? A new study helps answer these questions.
Scientists have been able to observe liquid water at single points by drilling holes, but those observations are limited. An improved technique developed by a graduate student at Columbia University’s Lamont-Doherty Earth Observatory and her colleagues is now expanding that view across entire regions, and across seasons for the first time, by making it possible to use airborne ice-penetrating radar to reveal meltwater’s life under the ice throughout the year.
The first results, just published in the journal Geophysical Research Letters, reveal extensive winter water storage beneath the ice. They suggest that glaciers’ response to melting depends not only on the rate at which meltwater flows down, but also on the amount of water stored beneath the ice through the winter, and on the topography and permeability of the land below, said the study’s lead author, Columbia graduate student Winnie Chu.
“The distribution of meltwater evolves constantly, switching from one location to another,” said Chu. “By knowing how this distribution changes seasonally, we can better understand the spatial linkage between ice and water flow.” Chu said that more meltwater is produced as temperatures rise, and the study suggests that Greenland has the potential to store some of it at the base of the ice. This could potentially mediate the impact of meltwater on summer ice flow by maintaining stable subglacial water pressures through the year, she said.
…[/font]
The illustration shows where water pools in winter and how it flows during the melt season. Illustration: Winnie Chu
…[/font]
http://dx.doi.org/10.1002/2016GL071538January 5, 2017
[font size=4]Exploring Where Liquid Goes, Even in Winter[/font]
[font size=3]When summer temperatures rise in Greenland and the melt season begins, water pools on the surface, and sometimes disappears down holes in the ice. That water may eventually reach bedrock, creating a slipperier, faster slide for glaciers. But where does it go once it gets there, and what happens to it in the winter? A new study helps answer these questions.
Scientists have been able to observe liquid water at single points by drilling holes, but those observations are limited. An improved technique developed by a graduate student at Columbia University’s Lamont-Doherty Earth Observatory and her colleagues is now expanding that view across entire regions, and across seasons for the first time, by making it possible to use airborne ice-penetrating radar to reveal meltwater’s life under the ice throughout the year.
The first results, just published in the journal Geophysical Research Letters, reveal extensive winter water storage beneath the ice. They suggest that glaciers’ response to melting depends not only on the rate at which meltwater flows down, but also on the amount of water stored beneath the ice through the winter, and on the topography and permeability of the land below, said the study’s lead author, Columbia graduate student Winnie Chu.
“The distribution of meltwater evolves constantly, switching from one location to another,” said Chu. “By knowing how this distribution changes seasonally, we can better understand the spatial linkage between ice and water flow.” Chu said that more meltwater is produced as temperatures rise, and the study suggests that Greenland has the potential to store some of it at the base of the ice. This could potentially mediate the impact of meltwater on summer ice flow by maintaining stable subglacial water pressures through the year, she said.
…[/font]
The illustration shows where water pools in winter and how it flows during the melt season. Illustration: Winnie Chu
…[/font]