Dynamic perennial firn aquifer on an Arctic glacier
K. Christianson, J. Kohler, R. B. Alley, C. Nuth, and W. J. van Pelt
Geophysical Research Letters (16 March 2015)
DOI: 10.1002/2014GL062806
Ice-penetrating radar and GPS observations reveal a perennial firn aquifer (PFA) on a Svalbard ice field, similar to those recently discovered in southeastern Greenland. A bright, widespread radar reflector separates relatively dry and water-saturated firn. This surface, the phreatic firn water table, is deeper beneath local surface elevation maxima, shallower in surface lows, and steeper where the surface is steep. The reflector crosscuts snow stratigraphy; we use the apparent deflection of accumulation layers due to the higher dielectric permittivity below the water table to infer that the firn pore space becomes progressively more saturated as depth increases. Our observations indicate that PFAs respond rapidly (subannually) to surface forcing, and are capable of providing significant input to the englacial hydrology system.
keywords: glacier hydrology; firn aquifer; ice sheet dynamics; ice-penetrating radar; 0720 Glaciers; 0774 Dynamics; 0776 Glaciology; 1863 Snow and ice; 9315 Arctic region