Ice sheets
A buried Antarctic lake drained through hydrofracture
Open access · cc by · source: Europe PMC
Ground-penetrating radar caught a buried meltwater lake draining through vertical fractures at an East Antarctic ice-shelf grounding zone.
Study at a glance
- Design
- Other — GPR before/after collapse plus SNOWPACK and Sentinel-1 monitoring of a buried meltwater lake
- N
- N=1 · Single buried lake (~1.5 billion m³) at an East Antarctic ice-shelf grounding zone
- Population
- Buried meltwater lake on the grounding zone of an East Antarctic ice shelf
- Outcome
- Drainage through vertical fractures and implications for ice-shelf weakening
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
The lake sat about 3.5 m below the surface with ~1.5 billion m³ of water and drained through preexisting lake-bed fractures. DEM differencing showed a multi-metre surface drop, and Sentinel-1 backscatter jumped during March–April 2016. Fractures can advect onto the floating shelf and threaten buttressing.
Methodology
The team surveyed a buried lake on the grounding zone of an East Antarctic ice shelf with ground-penetrating radar before and after collapse, combined that with SNOWPACK energy-balance modeling forced by a nearby weather station, and tracked surface-height and Sentinel-1 backscatter changes.
Limitations
This is one lake at one grounding-zone site, not a continent-wide census. Volume is likely underestimated because the GPR grid missed the southern shoreline, and the study cannot prove that these fractures currently reach the ice-shelf front or trigger collapse.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
A buried East Antarctic grounding-zone lake ~3.5 m down, holding ~1.5 billion m³, drained through preexisting fractures. REMA DEM differencing showed a multi-metre surface drop, and Sentinel-1 backscatter jumped during March–April 2016. GPR supplied the water volume and fracture geometry; the satellite record timed the collapse. This is one lake, not a continent-wide census.
Evidence for the claim as stated.
GPR before and after collapse showed a buried East Antarctic grounding-zone lake ~3.5 m below the surface, average water depth 2.2 m (maximum 4.6 m), and ~1.5 billion m³ of water that drained through preexisting lake-bed fractures. Post-collapse profiles showed ~1 m vertical discontinuities. REMA and Sentinel-1 timed a multi-metre surface drop and a March–April 2016 backscatter jump; volume is likely underestimated because the GPR grid missed the southern shoreline.
Evidence for the claim as stated.
Ice-penetrating radar, GPR and C-band InSAR are not interchangeable ‘radar observations.’ BedMachine infers thickness from IceBridge plus mass conservation and ship bathymetry; the Antarctic paper images a single buried lake at 400 MHz; the landslide paper measures surface motion at 90 m without seeing the subsurface. Combining 7.42 m of Greenland sea-level potential with 1.5 billion m³ of buried lake water as two ice-sheet radar volumes mixes a continent-scale product with one grounding-zone survey.
Evidence for the claim as stated.
Even within ice radar, grid spacing is not resolution. BedMachine’s 150 m grid is ~1 km where kriging/RTopo-2 fill, and radar thickness uncertainty is ~50 m; thinning since 2003–2008 is ignored except where it exceeds that error. GPR lake volume is a lower bound because the survey missed the southern shore. A student who treats both as ‘150 m truth’ will overstate how well the bed or the lake is known.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
Ice-penetrating radar, GPR and C-band InSAR are not interchangeable ‘radar observations.’ BedMachine infers thickness from IceBridge plus mass conservation and ship bathymetry; the Antarctic paper images a single buried lake at 400 MHz; the landslide paper measures surface motion at 90 m without seeing the subsurface. Combining 7.42 m of Greenland sea-level potential with 1.5 billion m³ of buried lake water as two ice-sheet radar volumes mixes a continent-scale product with one grounding-zone survey.
Even within ice radar, grid spacing is not resolution. BedMachine’s 150 m grid is ~1 km where kriging/RTopo-2 fill, and radar thickness uncertainty is ~50 m; thinning since 2003–2008 is ignored except where it exceeds that error. GPR lake volume is a lower bound because the survey missed the southern shore. A student who treats both as ‘150 m truth’ will overstate how well the bed or the lake is known.
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