The Greenland firn aquifer: Discovery and subsequent interdisciplinary field measurements
Abstract
The first direct observation of the firn aquifer within the Greenland ice sheet occurred in April 2011 while our group was extracting firn cores for accumulation measurements in SE Greenland. Once at the surface liquid water drained from the core segment acquired at10 m depth. Since this was three months prior to surface melt it was obvious, but unexpected, that this liquid water had been stored at depth within the firn throughout at least the previous winter. We mapped the local extent of the top of the aquifer (water table) as a bright horizontally continuous reflector in the GPR echogram. The extent and water table depth from the GPR agreed with the NASA Operation IceBridge airborne Accumulation Radar and therefore we were able to map the near ice sheet-wide extent and depth to water table using the previously flown flight lines. Since this discovery our group has taken an interdisciplinary approach to investigating the extent, volume, flow rate, recharge process and rate, age, and sustainability mechanisms. In addition to radar we have used active seismic refraction, magnetic resonance soundings, and a suite of groundwater hydrology measurements. For this presentation we present a summary of some previous results along with first measurements of recharge rates, converging evidence of firn aquifer formation age, and expansion of its extent.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C13C1308F
- Keywords:
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- 0720 Glaciers;
- CRYOSPHERE;
- 0726 Ice sheets;
- CRYOSPHERE;
- 0730 Ice streams;
- CRYOSPHERE;
- 0776 Glaciology;
- CRYOSPHERE