Sentinel-1 detects firn aquifers in the Greenland ice sheet

Firn aquifers in Greenland store liquid water within the upper ice sheet and impact the hydrological system. Their location and area have been estimated with airborne radar sounder surveys (Operation IceBridge, OIB). However, the OIB coverage is limited to narrow flight lines, offering an incomplete...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Brangers, I, Lievens, Hans, Miege, C., Demuzere, Matthias, Brucker, L., De Lannoy, G. J. M.
Format: Article in Journal/Newspaper
Language:English
Published: 2020
Subjects:
Earth and Environmental Sciences
MELTWATER STORAGE
SURFACE-PROPERTIES
RADAR
SCATTEROMETER
SNOW
Greenland
The Sentinel
Ice Sheet
Online Access:https://biblio.ugent.be/publication/8684945
http://hdl.handle.net/1854/LU-8684945
https://doi.org/10.1029/2019GL085192
https://biblio.ugent.be/publication/8684945/file/8684946
Description
Summary:Firn aquifers in Greenland store liquid water within the upper ice sheet and impact the hydrological system. Their location and area have been estimated with airborne radar sounder surveys (Operation IceBridge, OIB). However, the OIB coverage is limited to narrow flight lines, offering an incomplete view. Here, we show the ability of satellite radar measurements from Sentinel-1 to map firn aquifers across all of Greenland at 1 km(2) resolution. The detection of aquifers relies on a delay in the freezing of meltwater within the firn above the water table, causing a distinctive pattern in the radar backscatter. The Sentinel-1 aquifer locations are in very good agreement with those detected along the OIB flight lines (Cohen's kappa = 0.84). The total aquifer area is estimated at 54,800 km(2). With continuity of Sentinel-1 ensured until 2030, our study lays a foundation for monitoring the future response of firn aquifers to climate change.

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