Direct Evidence of Meltwater Flow Within a Firn Aquifer in Southeast Greenland

Within the lower percolation zone of the southeastern Greenland ice sheet, meltwater has accumulated within the firn pore space, forming extensive firn aquifers. Previously, it was unclear if these aquifers stored or facilitated meltwater runoff. Following mixing of a saline solution into boreholes...

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Bibliographic Details
Published in:Geophysical research letters 2018-01, Vol.45 (1), p.207-215
Main Authors: Miller, Olivia, Solomon, D. Kip, Miège, Clément, Koenig, Lora, Forster, Richard, Schmerr, Nicholas, Ligtenberg, Stefan R. M., Montgomery, Lynn
Format: Article
Language:English
Subjects:
Aquifers
borehole dilution test
Boreholes
Compacting
Conductance
Crevasses
Dilution
Discharge
Firn
firn aquifer
Freshwater
Glaciation
Greenland ice sheet
Ice
Ice accumulation
Ice sheets
Inland water environment
mass balance
Meltwater
meltwater flow
Oceans
Percolation
Resistance
Runoff
Saline solutions
Sea level
Snow
Storage
Water flow
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Summary:Within the lower percolation zone of the southeastern Greenland ice sheet, meltwater has accumulated within the firn pore space, forming extensive firn aquifers. Previously, it was unclear if these aquifers stored or facilitated meltwater runoff. Following mixing of a saline solution into boreholes within the aquifer, we observe that specific conductance measurements decreased over time as flowing freshwater diluted the saline mixture in the borehole. These tests indicate that water flows through the aquifer with an average specific discharge of 4.3 × 10−6 m/s (σ = 2.5 × 10−6 m/s). The specific discharge decreases dramatically to 0 m/s, defining the bottom of the aquifer between 30 to 50 m depth. The observed flow indicates that the firn pore space is a short‐term (
ISSN:0094-8276
1944-8007
DOI:10.1002/2017GL075707