Sunlight Absorption on the Greenland ice sheet Experiment (SAGE)”
When: Tuesday, January 07 2014, 12:00pm - 1:30pm
Where: 041 Haldeman Center
Contact : Lee McDavid, 603-646-1278


Chris Polashenski
Chris Polashenski, PhD
Chris Polashenski, PhD, Research Geophysicist, Cold Regions Research and Engineering Laborator (CRREL)


Big changes are happening on the Greenland Ice Sheet. Trends show increasing melt extent, longer melt seasons, lower surface albedo, higher ice temperatures, and increased ice flow. All of these are important because the Greenland Ice Sheet is a major potential contributor to sea level rise. Zoe Courville, PhD, and Chris Polashenski, PhD, at the US Army Cold Regions Research and Engineering Laboratory (CRREL) are leading a series of studies aimed at better understanding how albedo feedbacks are contributing to enhanced melt on the ice sheet. These studies are organized around large scale traverses of the ice sheet, observing albedo, snow properties, light absorbing impurity concentrations, and firn temperatures, and synthesizing data from the traverses with remote sensing observations and large scale modeling. The first traverse occurred from April-June 2013 and preliminary results will be presented. Part of the traverse followed the route pioneered by the godfather of Greenland research, Carl Benson. Replicating Benson's observations shows substantial warming has occurred in mid altitudes of the ice sheet. The traverse also found enhanced black carbon concentrations in the 2012 melt layer. We analyze these to assess the role that black carbon deposition may have played in the 2012 melt event, and compare the impacts of black carbon with grain metamorphosis. Finally we discuss plans for 2014 and invite comments and discussion.


Dr. Polashenski is a research geophysicist with the Terrestrial and Cryospheric Sciences Branch at CRREL specializing in the physical properties of sea ice and snow.  He received his undergraduate degree and a doctoral degree in material engineering from the Thayer School of Engineering at Dartmouth, and is a veteran of Dartmouth's NSF IGERT program on polar environmental change. Now he leads research programs exploring processes of the cryosphere, particularly those that influence energy balance feedbacks, such as melt pond formation on sea ice, aerosol deposition in snow, and snow grain metamorphosis.


Sponsored by the Institute of Arctic Studies at the Dickey Center and the IGERT Dialogues in Polar Science & Society.


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