TY - JOUR
T1 - Concurrent superimposed ice formation and meltwater runoff on Greenland’s ice slabs
AU - Tedstone, Andrew
AU - Machguth, Horst
AU - Clerx, Nicole
AU - Jullien, Nicolas
AU - Picton, Hannah
AU - Ducrey, Julien
AU - van As, Dirk
AU - Colosio, Paolo
AU - Tedesco, Marco
AU - Lhermitte, Stef
N1 - Publisher Copyright:
© The Author(s) 2025.
PY - 2025/5/14
Y1 - 2025/5/14
N2 - Rivers and slush fields on the Greenland Ice Sheet increasingly develop in locations where the accumulation zone hosts near-impermeable ice slabs. However, the division between runoff versus retention in these areas remains unmeasured. We present field measurements of superimposed ice formation onto slabs around the visible runoff limit. The quantity of superimposed ice varies by proximity to visible surface water and the surface slope, highlighting that meltwater can flow laterally before refreezing. We use heat conduction modelling and radar observations of autumn wetness to show that in our field area in 2022, 65% of superimposed ice formed during summer and the rest during autumn in the relict supraglacial hydrological network. Overall, 84% of melt around the visible runoff limit refroze. Ice-sheet-wide we estimate that slabs refroze 56 gigatonnes of melt (26-69 gigatonnes according to slab extent) between 2017 and 2022. Slabs are thus both hotspots of refreezing and emerging zones of runoff.
AB - Rivers and slush fields on the Greenland Ice Sheet increasingly develop in locations where the accumulation zone hosts near-impermeable ice slabs. However, the division between runoff versus retention in these areas remains unmeasured. We present field measurements of superimposed ice formation onto slabs around the visible runoff limit. The quantity of superimposed ice varies by proximity to visible surface water and the surface slope, highlighting that meltwater can flow laterally before refreezing. We use heat conduction modelling and radar observations of autumn wetness to show that in our field area in 2022, 65% of superimposed ice formed during summer and the rest during autumn in the relict supraglacial hydrological network. Overall, 84% of melt around the visible runoff limit refroze. Ice-sheet-wide we estimate that slabs refroze 56 gigatonnes of melt (26-69 gigatonnes according to slab extent) between 2017 and 2022. Slabs are thus both hotspots of refreezing and emerging zones of runoff.
UR - http://www.scopus.com/inward/record.url?scp=105005105702&partnerID=8YFLogxK
U2 - 10.1038/s41467-025-59237-9
DO - 10.1038/s41467-025-59237-9
M3 - Article
AN - SCOPUS:105005105702
SN - 2041-1723
VL - 16
JO - Nature Communications
JF - Nature Communications
M1 - 4494
ER -