Hydraulic Conductivity of a Firn Aquifer in Southeast Greenland

Frontiers in Digital Humanities

Brucker, Ludovic¹  Miller, Olivia L.²  Solomon, D. Kip²  Montgomery, Lynn N.³  Schmerr, Nicholas³  Forster, Richard R.⁴  Mige, Clment⁴  Ligtenberg, Stefan R. M.⁵  Legchenko, Anatoly⁶  Koenig, Lora S.⁷ 

[1] Cryospheric Sciences Laboratory, Goddard Space Flight Center (NASA), Greenbelt, MD, United States;Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, United States;Department of Geology, University of Maryland, College Park, College Park, MD, United States;Geography Department, University of Utah, Salt Lake City, UT, United States;Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, Netherlands;Institute of Research for Development, University Grenoble Alps, IGE, Grenoble, France;National Snow and Ice Data Center, University of Colorado Boulder, Boulder, CO, United States

关键词: firn aquifer;    hydraulic conductivity;    Meltwater runoff;    Meltwater flow;    Aquifer tests;    Slug tests;    meltwater retention;    Greenland ice sheet;    Helheim Glacier;   

DOI  :  10.3389/feart.2017.00038

学科分类：社会科学、人文和艺术（综合）

来源: Frontiers

【 摘 要 】

Some regions of the Greenland ice sheet, where snow accumulation and melt rates are high, currently retain substantial volumes of liquid water within the firn pore space throughout the year. These firn aquifers, found between ~10-30 m below the snow surface, may significantly affect sea level rise by storing or draining surface meltwater. The hydraulic gradient and the hydraulic conductivity control flow of meltwater through the firn. Here we describe the hydraulic conductivity of the firn aquifer estimated from slug tests and aquifer tests at six sites located upstream of Helheim Glacier in southeastern Greenland. We conducted slug tests using a novel instrument, a piezometer with a heated tip that melts itself into the ice sheet. Hydraulic conductivity ranges between 2.5x10-5 and 1.1x10-3 m/s. The geometric mean of hydraulic conductivity of the aquifer is 2.7x10-4 m/s with a geometric standard deviation of 1.4 from both depth specific slug tests (analyzed using the Hvorslev method) and aquifer tests during the recovery period. Hydraulic conductivity is relatively consistent between boreholes and only decreases slightly with depth. The hydraulic conductivity of the firn aquifer is crucial for determining flow rates and patterns within the aquifer, which inform hydrologic models of the aquifer, its relation to the broader glacial hydrologic system, and its effect on sea level rise.

【 授权许可】

CC BY