C22B-04
Efficient removal of meltwater runoff through supraglacial streams and rivers on the southwestern Greenland Ice Sheet
Tuesday, 15 December 2015: 11:05
3007 (Moscone West)
Laurence C Smith1, Kang Yang2, Lincoln H Pitcher2, Brandon T Overstreet3, Asa K Rennermalm4, Vena W. Chu5, Jonathan Ryan6, Alun Hubbard6, Matthew G Cooper2, Marco Tedesco7, Thomas L Mote8, Kathy Young9 and Alberto Behar10, (1)UCLA, Los Angeles, CA, United States, (2)University of California Los Angeles, Los Angeles, CA, United States, (3)University of Wyoming, Laramie, WY, United States, (4)Rutgers University New Brunswick, New Brunswick, NJ, United States, (5)University of California Berkeley, Berkeley, CA, United States, (6)Aberystwyth University, Aberystwyth, United Kingdom, (7)CUNY City College of New York, New York, NY, United States, (8)University of Georgia, Athens, GA, United States, (9)Polar Field Services Littleton, Littleton, CO, United States, (10)NASA Jet Propulsion Laboratory, (deceased), Pasadena, CA, United States
Abstract:
Supraglacial streams and rivers flowing on the Greenland Ice Sheet have received little physical study. We present remotely sensed (UAV, WorldView) and in situ (Acoustic Doppler Current Profiler, Lagrangian drifters) measurements of supraglacial river drainage pattern, hydraulic properties, and discharge in the Kangerlussuaq region. This area of the ice sheet is characterized by large, well-organized supraglacial stream/river networks that efficiently drain the ice surface with minimal retention of surface water, with river moulins being the the dominant physical mechanism by which surface meltwater enters the ice sheet. An intensive 2015 field campaign acquired novel datasets of watershed extent, drainage pattern, ablation rate, albedo and discharge for a ~70 km2 mid-elevation ice catchment ("Rio Behar"), including a continuous 72-hour record of discharge and water temperature in a supraglacial river upstream of its terminal moulin. We conclude that this area of the ice sheet is efficiently drained by supraglacial stream/river networks, that ice-surface DEMs alone cannot fully describe supraglacial drainage and its connection to subglacial systems; and that in situ measurements of supraglacial river discharge offer a unique opportunity to test runoff predictions of regional climate models.
