Multi-modal albedo distributions in the ablation area of the southwestern Greenland Ice Sheet
Surface albedo is a key variable controlling solar radiation absorbed at the Greenland Ice Sheet (GrIS) surface and, thus, meltwater production. Recent decline in surface albedo over the GrIS has been linked to enhanced snow grain metamorphic rates, earlier snowmelt, and amplified melt–albedo feedba...
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2015
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ftdoajarticles:oai:doaj.org/article:1a9ed1acf75048489d018c8e0eba8359 2023-05-15T16:28:02+02:00 Multi-modal albedo distributions in the ablation area of the southwestern Greenland Ice Sheet S. E. Moustafa A. K. Rennermalm L. C. Smith M. A. Miller J. R. Mioduszewski L. S. Koenig M. G. Hom C. A. Shuman 2015-05-01T00:00:00Z https://doi.org/10.5194/tc-9-905-2015 https://doaj.org/article/1a9ed1acf75048489d018c8e0eba8359 EN eng Copernicus Publications http://www.the-cryosphere.net/9/905/2015/tc-9-905-2015.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-9-905-2015 https://doaj.org/article/1a9ed1acf75048489d018c8e0eba8359 The Cryosphere, Vol 9, Iss 3, Pp 905-923 (2015) Environmental sciences GE1-350 Geology QE1-996.5 article 2015 ftdoajarticles https://doi.org/10.5194/tc-9-905-2015 2022-12-31T01:34:37Z Surface albedo is a key variable controlling solar radiation absorbed at the Greenland Ice Sheet (GrIS) surface and, thus, meltwater production. Recent decline in surface albedo over the GrIS has been linked to enhanced snow grain metamorphic rates, earlier snowmelt, and amplified melt–albedo feedback from atmospheric warming. However, the importance of distinct surface types on ablation area albedo and meltwater production is still relatively unknown. In this study, we analyze albedo and ablation rates using in situ and remotely sensed data. Observations include (1) a new high-quality in situ spectral albedo data set collected with an Analytical Spectral Devices Inc. spectroradiometer measuring at 325–1075 nm along a 1.25 km transect during 3 days in June 2013; (2) broadband albedo at two automatic weather stations; and (3) daily MODerate Resolution Imaging Spectroradiometer (MODIS) albedo (MOD10A1) between 31 May and 30 August 2012 and 2013. We find that seasonal ablation area albedos in 2013 have a bimodal distribution, with snow and ice facies characterizing the two peaks. Our results show that a shift from a distribution dominated by high to low albedos corresponds to an observed melt rate increase of 51.5% (between 10–14 July and 20–24 July 2013). In contrast, melt rate variability caused by albedo changes before and after this shift was much lower and varied between ~10 and 30% in the melting season. Ablation area albedos in 2012 exhibited a more complex multimodal distribution, reflecting a transition from light to dark-dominated surface, as well as sensitivity to the so called "dark-band" region in southwest Greenland. In addition to a darkening surface from ice crystal growth, our findings demonstrate that seasonal changes in GrIS ablation area albedos are controlled by changes in the fractional coverage of snow, bare ice, and impurity-rich surface types. Thus, seasonal variability in ablation area albedos appears to be regulated primarily as a function of bare ice expansion at the expense of snow, ... Article in Journal/Newspaper Greenland Ice Sheet The Cryosphere Directory of Open Access Journals: DOAJ Articles Greenland The Cryosphere 9 3 905 923 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 S. E. Moustafa A. K. Rennermalm L. C. Smith M. A. Miller J. R. Mioduszewski L. S. Koenig M. G. Hom C. A. Shuman Multi-modal albedo distributions in the ablation area of the southwestern Greenland Ice Sheet |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Surface albedo is a key variable controlling solar radiation absorbed at the Greenland Ice Sheet (GrIS) surface and, thus, meltwater production. Recent decline in surface albedo over the GrIS has been linked to enhanced snow grain metamorphic rates, earlier snowmelt, and amplified melt–albedo feedback from atmospheric warming. However, the importance of distinct surface types on ablation area albedo and meltwater production is still relatively unknown. In this study, we analyze albedo and ablation rates using in situ and remotely sensed data. Observations include (1) a new high-quality in situ spectral albedo data set collected with an Analytical Spectral Devices Inc. spectroradiometer measuring at 325–1075 nm along a 1.25 km transect during 3 days in June 2013; (2) broadband albedo at two automatic weather stations; and (3) daily MODerate Resolution Imaging Spectroradiometer (MODIS) albedo (MOD10A1) between 31 May and 30 August 2012 and 2013. We find that seasonal ablation area albedos in 2013 have a bimodal distribution, with snow and ice facies characterizing the two peaks. Our results show that a shift from a distribution dominated by high to low albedos corresponds to an observed melt rate increase of 51.5% (between 10–14 July and 20–24 July 2013). In contrast, melt rate variability caused by albedo changes before and after this shift was much lower and varied between ~10 and 30% in the melting season. Ablation area albedos in 2012 exhibited a more complex multimodal distribution, reflecting a transition from light to dark-dominated surface, as well as sensitivity to the so called "dark-band" region in southwest Greenland. In addition to a darkening surface from ice crystal growth, our findings demonstrate that seasonal changes in GrIS ablation area albedos are controlled by changes in the fractional coverage of snow, bare ice, and impurity-rich surface types. Thus, seasonal variability in ablation area albedos appears to be regulated primarily as a function of bare ice expansion at the expense of snow, ... |
format |
Article in Journal/Newspaper |
author |
S. E. Moustafa A. K. Rennermalm L. C. Smith M. A. Miller J. R. Mioduszewski L. S. Koenig M. G. Hom C. A. Shuman |
author_facet |
S. E. Moustafa A. K. Rennermalm L. C. Smith M. A. Miller J. R. Mioduszewski L. S. Koenig M. G. Hom C. A. Shuman |
author_sort |
S. E. Moustafa |
title |
Multi-modal albedo distributions in the ablation area of the southwestern Greenland Ice Sheet |
title_short |
Multi-modal albedo distributions in the ablation area of the southwestern Greenland Ice Sheet |
title_full |
Multi-modal albedo distributions in the ablation area of the southwestern Greenland Ice Sheet |
title_fullStr |
Multi-modal albedo distributions in the ablation area of the southwestern Greenland Ice Sheet |
title_full_unstemmed |
Multi-modal albedo distributions in the ablation area of the southwestern Greenland Ice Sheet |
title_sort |
multi-modal albedo distributions in the ablation area of the southwestern greenland ice sheet |
publisher |
Copernicus Publications |
publishDate |
2015 |
url |
https://doi.org/10.5194/tc-9-905-2015 https://doaj.org/article/1a9ed1acf75048489d018c8e0eba8359 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet The Cryosphere |
genre_facet |
Greenland Ice Sheet The Cryosphere |
op_source |
The Cryosphere, Vol 9, Iss 3, Pp 905-923 (2015) |
op_relation |
http://www.the-cryosphere.net/9/905/2015/tc-9-905-2015.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-9-905-2015 https://doaj.org/article/1a9ed1acf75048489d018c8e0eba8359 |
op_doi |
https://doi.org/10.5194/tc-9-905-2015 |
container_title |
The Cryosphere |
container_volume |
9 |
container_issue |
3 |
container_start_page |
905 |
op_container_end_page |
923 |
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1766017647273574400 |