Challenges in predicting Greenland supraglacial lake drainages at the regional scale
A leading hypothesis for the mechanism of fast supraglacial lake drainages is that transient extensional stresses briefly allow crevassing in otherwise compressional ice flow regimes. Lake water can then hydrofracture a crevasse to the base of the ice sheet, and river inputs can maintain this connec...
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Copernicus Publications
2021
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Online Access: | https://doi.org/10.5194/tc-15-1455-2021 https://doaj.org/article/0d8d082c4ad24e489bca9c692c9440b7 |
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ftdoajarticles:oai:doaj.org/article:0d8d082c4ad24e489bca9c692c9440b7 2023-05-15T16:28:22+02:00 Challenges in predicting Greenland supraglacial lake drainages at the regional scale K. Poinar L. C. Andrews 2021-03-01T00:00:00Z https://doi.org/10.5194/tc-15-1455-2021 https://doaj.org/article/0d8d082c4ad24e489bca9c692c9440b7 EN eng Copernicus Publications https://tc.copernicus.org/articles/15/1455/2021/tc-15-1455-2021.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-15-1455-2021 1994-0416 1994-0424 https://doaj.org/article/0d8d082c4ad24e489bca9c692c9440b7 The Cryosphere, Vol 15, Pp 1455-1483 (2021) Environmental sciences GE1-350 Geology QE1-996.5 article 2021 ftdoajarticles https://doi.org/10.5194/tc-15-1455-2021 2022-12-31T04:44:17Z A leading hypothesis for the mechanism of fast supraglacial lake drainages is that transient extensional stresses briefly allow crevassing in otherwise compressional ice flow regimes. Lake water can then hydrofracture a crevasse to the base of the ice sheet, and river inputs can maintain this connection as a moulin. If future ice sheet models are to accurately represent moulins, we must understand their formation processes, timescales, and locations. Here, we use remote-sensing velocity products to constrain the relationship between strain rates and lake drainages across ∼ 1600 km 2 in Pâkitsoq, western Greenland, between 2002–2019. We find significantly more extensional background strain rates at moulins associated with fast-draining lakes than at slow-draining or non-draining lake moulins. We test whether moulins in more extensional background settings drain their lakes earlier, but we find insignificant correlation. To investigate the frequency at which strain-rate transients are associated with fast lake drainage, we examined Landsat-derived strain rates over 16 and 32 d periods at moulins associated with 240 fast-lake-drainage events over 18 years. A low signal-to-noise ratio, the presence of water, and the multi-week repeat cycle obscured any resolution of the hypothesized transient strain rates. Our results support the hypothesis that transient strain rates drive fast lake drainages. However, the current generation of ice sheet velocity products, even when stacked across hundreds of fast lake drainages, cannot resolve these transients. Thus, observational progress in understanding lake drainage initiation will rely on field-based tools such as GPS networks and photogrammetry. Article in Journal/Newspaper Greenland Ice Sheet The Cryosphere Directory of Open Access Journals: DOAJ Articles Fast Lake ENVELOPE(-108.251,-108.251,59.983,59.983) Greenland The Cryosphere 15 3 1455 1483 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 K. Poinar L. C. Andrews Challenges in predicting Greenland supraglacial lake drainages at the regional scale |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
A leading hypothesis for the mechanism of fast supraglacial lake drainages is that transient extensional stresses briefly allow crevassing in otherwise compressional ice flow regimes. Lake water can then hydrofracture a crevasse to the base of the ice sheet, and river inputs can maintain this connection as a moulin. If future ice sheet models are to accurately represent moulins, we must understand their formation processes, timescales, and locations. Here, we use remote-sensing velocity products to constrain the relationship between strain rates and lake drainages across ∼ 1600 km 2 in Pâkitsoq, western Greenland, between 2002–2019. We find significantly more extensional background strain rates at moulins associated with fast-draining lakes than at slow-draining or non-draining lake moulins. We test whether moulins in more extensional background settings drain their lakes earlier, but we find insignificant correlation. To investigate the frequency at which strain-rate transients are associated with fast lake drainage, we examined Landsat-derived strain rates over 16 and 32 d periods at moulins associated with 240 fast-lake-drainage events over 18 years. A low signal-to-noise ratio, the presence of water, and the multi-week repeat cycle obscured any resolution of the hypothesized transient strain rates. Our results support the hypothesis that transient strain rates drive fast lake drainages. However, the current generation of ice sheet velocity products, even when stacked across hundreds of fast lake drainages, cannot resolve these transients. Thus, observational progress in understanding lake drainage initiation will rely on field-based tools such as GPS networks and photogrammetry. |
format |
Article in Journal/Newspaper |
author |
K. Poinar L. C. Andrews |
author_facet |
K. Poinar L. C. Andrews |
author_sort |
K. Poinar |
title |
Challenges in predicting Greenland supraglacial lake drainages at the regional scale |
title_short |
Challenges in predicting Greenland supraglacial lake drainages at the regional scale |
title_full |
Challenges in predicting Greenland supraglacial lake drainages at the regional scale |
title_fullStr |
Challenges in predicting Greenland supraglacial lake drainages at the regional scale |
title_full_unstemmed |
Challenges in predicting Greenland supraglacial lake drainages at the regional scale |
title_sort |
challenges in predicting greenland supraglacial lake drainages at the regional scale |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-15-1455-2021 https://doaj.org/article/0d8d082c4ad24e489bca9c692c9440b7 |
long_lat |
ENVELOPE(-108.251,-108.251,59.983,59.983) |
geographic |
Fast Lake Greenland |
geographic_facet |
Fast Lake Greenland |
genre |
Greenland Ice Sheet The Cryosphere |
genre_facet |
Greenland Ice Sheet The Cryosphere |
op_source |
The Cryosphere, Vol 15, Pp 1455-1483 (2021) |
op_relation |
https://tc.copernicus.org/articles/15/1455/2021/tc-15-1455-2021.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-15-1455-2021 1994-0416 1994-0424 https://doaj.org/article/0d8d082c4ad24e489bca9c692c9440b7 |
op_doi |
https://doi.org/10.5194/tc-15-1455-2021 |
container_title |
The Cryosphere |
container_volume |
15 |
container_issue |
3 |
container_start_page |
1455 |
op_container_end_page |
1483 |
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1766018005022539776 |