Proglacial lakes speed Greenland outlet glaciers
Lake-terminating Greenland outlet glaciers flow much faster near their fronts than otherwise similar land-terminating glaciers.
Source
Ice-marginal proglacial lakes enhance outlet glacier velocities across Greenland
Study at a glance
- Design
- Other — Paired comparison of lake- vs land-terminating Greenland outlet glaciers with ITS_LIVE velocities
- N
- N=102 · 102 lake-terminating outlets paired with land-terminating counterparts
- Population
- Greenland outlet glaciers terminating in ice-marginal lakes vs on land
- Outcome
- Near-terminus ice-surface velocity enhancement associated with proglacial lakes
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
The authors paired 102 lake-terminating outlet glaciers with land-terminating glaciers, sampled ITS_LIVE ice-surface velocities along flowlines from 500 m to 9.5 km inland, and compared 2015–2019 (plus 2000) speeds with ice-marginal lake area.
What they found
In 2017, terminus velocity of lake-terminating glaciers was 231% higher than land-terminating glaciers. Median speeds were 43 versus 36 m yr−1 overall, and 43 versus 13 m yr−1 at 500 m inland. About 44% of lake-terminating glaciers accelerate toward the terminus, versus 3.9% of land-terminating glaciers. Effects are significant from about 3.5 km inland to the margin.
The limits
What it doesn't show
The study does not measure calving rates or submarine melt directly, so the mechanical cause of faster flow is inferred. Lake-area–velocity relationships are noisy, and some sectors have small samples. Elevation, slope, and aspect were similar between groups except steeper land-terminating fronts.
Key terms
- Ice-marginal proglacial lake (IML)
- A lake in contact with the ice-sheet margin, formed as meltwater ponds in overdeepenings exposed by retreat.
- Outlet glacier
- A fast-flowing ice stream that drains the ice sheet through a distinct trunk to the margin.
- ITS_LIVE
- A satellite feature-tracking velocity product (here 120 m Landsat-based) used to map ice-surface speed.
Flashcards
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Quiz yourself
Lake-terminating Greenland outlets in 2017 were faster at the terminus by:
Common questions
Do lakes affect ice only at the calving front?
No. Faster flow is strongest near the terminus but remains significant up to about 3.5 km inland (5 km in some years).
Is the 2017 pattern a one-year fluke?
No. Lake-terminating glaciers were also faster in 2000 and in every year from 2015 to 2019.
Does bigger lake always mean faster glacier?
Glaciers into lakes >30 km2 are about 40% faster than those into 1–5 km2 lakes, but medium lakes also host fast outliers.
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