Kinetic grain growth in firn induced by meltwater infiltration on the Greenland Ice Sheet

Gehl, Kirsten L.; Harper, Joel T.; Humphrey, Neil F.

doi:10.5194/tc-19-6791-2025

Articles | Volume 19, issue 12

https://doi.org/10.5194/tc-19-6791-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/tc-19-6791-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 19, issue 12

Research article

|

16 Dec 2025

Research article |

| 16 Dec 2025

Kinetic grain growth in firn induced by meltwater infiltration on the Greenland Ice Sheet

Kirsten L. Gehl, Joel T. Harper, and Neil F. Humphrey

Supplement

https://doi.org/10.5194/tc-19-6791-2025-supplement

Data sets

Firn core density and ice content at sites along the lower Expéditions Glaciologiques Internationales au Groenland (EGIG) line, Western Greenland, 2023 Joel Harper and Neil Humphrey https://doi.org/10.18739/A2DB7VR82

Firn temperature-time series to 25 meter depth at two sites along the west Expéditions Glaciologiques Internationales au Groenland (EGIG) line, Greenland 2022-2023 Joel Harper and Neil Humphrey https://doi.org/10.18739/A2DB7VS0N

Firn temperature-time series to 25 or 32 meter depth at sites along the west Expéditions Glaciologiques Internationales au Groenland (EGIG) line, Greenland 2023-2024 Joel Harper and Neil Humphrey https://doi.org/10.18739/A28K74Z5S

Firn temperature-time series to 30 meter depth at five sites along the west Expéditions Glaciologiques Internationales au Groenland (EGIG) line, Greenland summer of 2019 Joel Harper and Neil Humphrey https://doi.org/10.18739/A2JM23H8X

ERA5-Land hourly data from 1950 to present Joaquín Muñoz Sabater https://doi.org/10.24381/cds.e2161bac

GC-Net Level 1 historical automated weather station data Konrad Steffen et al. https://doi.org/10.22008/FK2/VVXGUT

Short summary

The geometric form of snow grains governs snow compaction and the movement of air and water within the snow. We observed unexpectedly thick and deep layers of faceted snow grains in cores drilled along the flanks of the Greenland Ice Sheet. Based on field measurements and modeling, we find that meltwater infiltration and refreezing in the cold snow generates these grains. As more of the ice sheet is affected by melting, subsurface faceting of snow crystals may become increasingly important.