Ice sheets
Greenland’s hidden fjord floors in BedMachine v3
Open access · cc by · source: Europe PMC
A 150 m Greenland bed and fjord map raises sea-level potential by 7 cm and shows 30–100% more glaciers can meet warm Atlantic Water.
Study at a glance
- Design
- Other — Mass-conservation bed mapping combining ice-penetrating radar and ocean bathymetry
- N
- Greenland-wide BedMachine v3 product; volume 2.99×10^6 km³ — not a sample N
- Population
- Greenland Ice Sheet bed topography and adjacent ocean bathymetry
- Outcome
- Ice volume, sea-level potential (7.42 m), and ocean access to glacier fronts
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Ice volume is 2.99±0.02×10^6 km³; sea-level potential 7.42±0.05 m (7 cm above prior). Of 243 glaciers, 67 connect to ocean deeper than 200 m. Retreat patterns match retrograde beds; v2 beds were often ~100 m too high.
Methodology
Authors combined IceBridge radar, mass conservation where ice flows faster than 50 m/yr, and 30 bathymetry sources including OMG multibeam to map bed and fjords within 50 km of the coast at up to 150 m.
Limitations
True resolution is coarser (~1 km) where kriging/RTopo-2 fill gaps; radar thickness uncertainty is ~50 m; thinning since 2003–2008 is ignored except where it exceeds that error.
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.
This library holds 11 empirical papers on ice sheets with measured outcomes rather than reviews.
Evidence for the claim as stated.
A 150 m Greenland bed and fjord map raises sea-level potential by 7 cm and shows 30–100% more glaciers can meet warm Atlantic Water.
Evidence for the claim as stated.
A melt-season ANN or a giant-iceberg track is not a committed multi-metre sea-level number.
Evidence for the claim as stated.
BedMachine v3 combines IceBridge radar, mass conservation where ice flows faster than 50 m/yr, and 30 bathymetry sources including OMG multibeam, mapping bed and fjords within 50 km of the Greenland coast at up to 150 m. Ice volume is 2.99±0.02×10⁶ km³; sea-level potential 7.42±0.05 m (7 cm above prior). Of 243 glaciers, 67 connect to ocean deeper than 200 m. Retreat patterns match retrograde beds; v2 beds were often ~100 m too high. True resolution is coarser (~1 km) where kriging/RTopo-2 fill gaps; radar thickness uncertainty is ~50 m.
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.
A melt-season ANN or a giant-iceberg track is not a committed multi-metre sea-level number.
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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Same topic cluster — not a recommendation engine.