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Observations of Pronounced Greenland Ice Sheet Firn Warming and Implications for Runoff ProductionField measurements of shallow borehole temperatures in firn across the northern Greenland ice sheet are collected during May 2013. Sites first measured in 19521955 are revisited, showing long-term trends in firn temperature. Results indicate a pattern of substantial firn warming (up to +5.7C) at midlevel elevations (1400-2500 m) and little temperature change at high elevations (2500 m). We find that latent heat transport into the firn due to meltwater percolation drives the observed warming. Modeling shows that heat is stored at depth for several years, and energy delivered from consecutive melt events accumulates in the firn. The observed warming is likely not yet in equilibrium with recent melt production rates but captures the progression of sites in the percolation facies toward net runoff production.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Polashenski, Chris (Army Cold Regions Research and Engineering Lab. Fort Wainright, AK, United States)
Courville, Zoe (Dartmouth Coll. Hanover, NH, United States)
Benson, Carl (Alaska Univ. Anchorage, AK, United States)
Wagner, Anna (Army Cold Regions Research and Engineering Lab. Fort Wainright, AK, United States)
Chen, Justin (Hanover High School Hanover, NH, United States)
Wong, Gifford (Dartmouth Coll. Hanover, NH, United States)
Hawley, Robert (Dartmouth Coll. Hanover, NH, United States)
Hall, Dorothy (NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
December 18, 2015
Publication Date
June 27, 2014
Publication Information
Publication: Geophysical Research Letters
Volume: 41
Issue: 12
Subject Category
Geosciences (General)
Report/Patent Number
Distribution Limits
ice sheet