Observations, theory, and modeling of the differential accumulation of Antarctic megadunes
Antarctic megadunes are characterized by significant spatial differences in accumulation rate, with higher accumulation on the windward side and near-zero accumulation on the lee side. This leads to spatial differences in physical properties of snow and surface roughness, as well as to the upwind mi...
Published in: | Journal of Geophysical Research: Earth Surface |
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Online Access: | https://doi.org/10.1002/2013Jf002844 http://infoscience.epfl.ch/record/196795 |
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ftinfoscience:oai:infoscience.tind.io:196795 2023-05-15T13:51:37+02:00 Observations, theory, and modeling of the differential accumulation of Antarctic megadunes Dadic, Ruzica Mott, Rebecca Horgan, Huw J. Lehning, Michael 2014-02-17T18:14:14Z https://doi.org/10.1002/2013Jf002844 http://infoscience.epfl.ch/record/196795 unknown Washington, Amer Geophysical Union doi:10.1002/2013Jf002844 ISI:000329873500021 http://infoscience.epfl.ch/record/196795 http://infoscience.epfl.ch/record/196795 Text 2014 ftinfoscience https://doi.org/10.1002/2013Jf002844 2023-02-13T22:19:15Z Antarctic megadunes are characterized by significant spatial differences in accumulation rate, with higher accumulation on the windward side and near-zero accumulation on the lee side. This leads to spatial differences in physical properties of snow and surface roughness, as well as to the upwind migration of the megadunes. While previous studies agree that megadunes are a result of complex interactions between wind, topography, and snow, it is not clear how they form or why they accumulate on the windward side. Here we use ICESat observations, dimensional analysis, and atmospheric flow modeling to investigate what conditions are responsible for the accumulation patterns and upwind migration of the megadunes. First, we use ICESat data to quantify the pattern of differential surface elevation change across the megadunes. We then use dimensional analysis based on supercritical-flow theory and atmospheric flow modeling to show that the megadunes topography and a stable atmosphere will always lead to upwind dune migration. We show that a combination of persistent katabatic winds, strong stability, and spatial variability in surface roughness is responsible for the accumulation on the upwind slope and hence the upwind migration of the megadunes. We further show that spatial differences in surface roughness are the primary control on accumulation magnitudes and hence dune migration velocity. The dune migration velocity in turn influences the degree of snow-metamorphism and the physical properties of snow that are relevant for paleoclimate records. Our findings pertain to the ongoing evolution of the megadunes, but their genesis remains an open question. Text Antarc* Antarctic EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne) Antarctic Journal of Geophysical Research: Earth Surface 118 4 2343 2353 |
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EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne) |
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ftinfoscience |
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Antarctic megadunes are characterized by significant spatial differences in accumulation rate, with higher accumulation on the windward side and near-zero accumulation on the lee side. This leads to spatial differences in physical properties of snow and surface roughness, as well as to the upwind migration of the megadunes. While previous studies agree that megadunes are a result of complex interactions between wind, topography, and snow, it is not clear how they form or why they accumulate on the windward side. Here we use ICESat observations, dimensional analysis, and atmospheric flow modeling to investigate what conditions are responsible for the accumulation patterns and upwind migration of the megadunes. First, we use ICESat data to quantify the pattern of differential surface elevation change across the megadunes. We then use dimensional analysis based on supercritical-flow theory and atmospheric flow modeling to show that the megadunes topography and a stable atmosphere will always lead to upwind dune migration. We show that a combination of persistent katabatic winds, strong stability, and spatial variability in surface roughness is responsible for the accumulation on the upwind slope and hence the upwind migration of the megadunes. We further show that spatial differences in surface roughness are the primary control on accumulation magnitudes and hence dune migration velocity. The dune migration velocity in turn influences the degree of snow-metamorphism and the physical properties of snow that are relevant for paleoclimate records. Our findings pertain to the ongoing evolution of the megadunes, but their genesis remains an open question. |
format |
Text |
author |
Dadic, Ruzica Mott, Rebecca Horgan, Huw J. Lehning, Michael |
spellingShingle |
Dadic, Ruzica Mott, Rebecca Horgan, Huw J. Lehning, Michael Observations, theory, and modeling of the differential accumulation of Antarctic megadunes |
author_facet |
Dadic, Ruzica Mott, Rebecca Horgan, Huw J. Lehning, Michael |
author_sort |
Dadic, Ruzica |
title |
Observations, theory, and modeling of the differential accumulation of Antarctic megadunes |
title_short |
Observations, theory, and modeling of the differential accumulation of Antarctic megadunes |
title_full |
Observations, theory, and modeling of the differential accumulation of Antarctic megadunes |
title_fullStr |
Observations, theory, and modeling of the differential accumulation of Antarctic megadunes |
title_full_unstemmed |
Observations, theory, and modeling of the differential accumulation of Antarctic megadunes |
title_sort |
observations, theory, and modeling of the differential accumulation of antarctic megadunes |
publisher |
Washington, Amer Geophysical Union |
publishDate |
2014 |
url |
https://doi.org/10.1002/2013Jf002844 http://infoscience.epfl.ch/record/196795 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
http://infoscience.epfl.ch/record/196795 |
op_relation |
doi:10.1002/2013Jf002844 ISI:000329873500021 http://infoscience.epfl.ch/record/196795 |
op_doi |
https://doi.org/10.1002/2013Jf002844 |
container_title |
Journal of Geophysical Research: Earth Surface |
container_volume |
118 |
container_issue |
4 |
container_start_page |
2343 |
op_container_end_page |
2353 |
_version_ |
1766255587755032576 |