Substantial contribution of slush to meltwater area across Antarctic ice shelves
Surface melting occurs across many of Antarctica’s ice shelves, mainly during the austral summer. The onset, duration, area, and fate of surface melting varies spatially and temporally, and the resultant surface meltwater is stored as ponded water (lakes) or as slush (saturated firn or snow), with i...
| Main Authors: | , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Nature Research
2024
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| Subjects: | |
| Online Access: | https://www.repository.cam.ac.uk/handle/1810/368470 https://doi.org/10.17863/CAM.108656 |
| Summary: | Surface melting occurs across many of Antarctica’s ice shelves, mainly during the austral summer. The onset, duration, area, and fate of surface melting varies spatially and temporally, and the resultant surface meltwater is stored as ponded water (lakes) or as slush (saturated firn or snow), with implications for ice-shelf hydrofracture, firn air content reduction, surface energy balance and thermal evolution. This study applies a machine learning method to the entire Landsat 8 image catalogue to derive monthly records of slush and ponded water area across 57 ice shelves between 2013 and 2021. We find that slush and ponded water occupy roughly equal areas of Antarctica’s ice shelves in January, with inter-regional variations in partitioning. This suggests that studies that neglect slush may substantially underestimate the area of ice shelves covered by surface meltwater. Further, we found that adjusting the surface albedo in a regional climate model to account for the lower albedo of surface meltwater resulted in 2.5 times greater snowmelt across five representative ice shelves. This extra melt is currently unaccounted for in regional climate models, which may lead to underestimates in projections of ice sheet melting and ice shelf stability. European Space Agency Climate Change Initiative fellowship (ESA ESRIN/ Contract No. 4000134462/21/I-NB) U.S. National Science Foundation (NSF) awards 1841607 and 2213702 Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) Grant OCENW.GROOT.2019.091 |
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