Stratigraphic Variation Within Polar Firn Caused by Differential Accumulation and Ice Flow: Interpretation of a 400 Mhz Short-Pulse Radar Profile from West Antarctica
We investigate causes of the stratigraphic variation revealed in a 177 km, 400 MHz short-pulse radar profile of firn from West Antarctica. The profile covers 56 m depth, and its direction was close to those of the ice flow and mean wind. The average, near-surface accumulation rates calculated from t...
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ftmaineuniv:oai:digitalcommons.library.umaine.edu:ers_facpub-1089 2024-09-15T17:43:47+00:00 Stratigraphic Variation Within Polar Firn Caused by Differential Accumulation and Ice Flow: Interpretation of a 400 Mhz Short-Pulse Radar Profile from West Antarctica Arcone, Steven A. Spikes, Vandy Blue Hamilton, Gordon S. 2005-01-01T08:00:00Z application/pdf https://digitalcommons.library.umaine.edu/ers_facpub/90 https://doi.org/10.3189/172756505781829151 https://digitalcommons.library.umaine.edu/context/ers_facpub/article/1089/viewcontent/hamilton_51.174.407.pdf unknown DigitalCommons@UMaine https://digitalcommons.library.umaine.edu/ers_facpub/90 doi:10.3189/172756505781829151 https://digitalcommons.library.umaine.edu/context/ers_facpub/article/1089/viewcontent/hamilton_51.174.407.pdf This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. In addition, no permission is required from the rights-holder(s) for educational uses. For other uses, you need to obtain permission from the rights-holder(s). Earth Science Faculty Scholarship Earth Sciences text 2005 ftmaineuniv https://doi.org/10.3189/172756505781829151 2024-07-24T05:38:40Z We investigate causes of the stratigraphic variation revealed in a 177 km, 400 MHz short-pulse radar profile of firn from West Antarctica. The profile covers 56 m depth, and its direction was close to those of the ice flow and mean wind. The average, near-surface accumulation rates calculated from the time delays of one radar horizon consistently show minima on leeward slopes and maxima on windward slopes, confirming an earlier study based on stake observations. The stratigraphic variation includes up to 30 m depth variation in individual horizons over tens of km, fold limbs that become progressively steeper with depth, and fold-hinge loci that change direction or propagate down-ice with depth over distances far less than predicted by the ice speeds. We use an accumulation rate model to show how local rate anomalies and the effect of ice speed upon a periodic variation in accumulation rate cause these phenomena, and we reproduce two key features seen in the stratigraphic variations. We conclude that the model provides an explanation of changes in spatial stratigraphy and local measures of accumulation history given the constraints of surface topography, ice and wind velocities, and a general accumulation rate for an area. Text Antarc* Antarctica West Antarctica The University of Maine: DigitalCommons@UMaine Journal of Glaciology 51 174 407 422 |
institution |
Open Polar |
collection |
The University of Maine: DigitalCommons@UMaine |
op_collection_id |
ftmaineuniv |
language |
unknown |
topic |
Earth Sciences |
spellingShingle |
Earth Sciences Arcone, Steven A. Spikes, Vandy Blue Hamilton, Gordon S. Stratigraphic Variation Within Polar Firn Caused by Differential Accumulation and Ice Flow: Interpretation of a 400 Mhz Short-Pulse Radar Profile from West Antarctica |
topic_facet |
Earth Sciences |
description |
We investigate causes of the stratigraphic variation revealed in a 177 km, 400 MHz short-pulse radar profile of firn from West Antarctica. The profile covers 56 m depth, and its direction was close to those of the ice flow and mean wind. The average, near-surface accumulation rates calculated from the time delays of one radar horizon consistently show minima on leeward slopes and maxima on windward slopes, confirming an earlier study based on stake observations. The stratigraphic variation includes up to 30 m depth variation in individual horizons over tens of km, fold limbs that become progressively steeper with depth, and fold-hinge loci that change direction or propagate down-ice with depth over distances far less than predicted by the ice speeds. We use an accumulation rate model to show how local rate anomalies and the effect of ice speed upon a periodic variation in accumulation rate cause these phenomena, and we reproduce two key features seen in the stratigraphic variations. We conclude that the model provides an explanation of changes in spatial stratigraphy and local measures of accumulation history given the constraints of surface topography, ice and wind velocities, and a general accumulation rate for an area. |
format |
Text |
author |
Arcone, Steven A. Spikes, Vandy Blue Hamilton, Gordon S. |
author_facet |
Arcone, Steven A. Spikes, Vandy Blue Hamilton, Gordon S. |
author_sort |
Arcone, Steven A. |
title |
Stratigraphic Variation Within Polar Firn Caused by Differential Accumulation and Ice Flow: Interpretation of a 400 Mhz Short-Pulse Radar Profile from West Antarctica |
title_short |
Stratigraphic Variation Within Polar Firn Caused by Differential Accumulation and Ice Flow: Interpretation of a 400 Mhz Short-Pulse Radar Profile from West Antarctica |
title_full |
Stratigraphic Variation Within Polar Firn Caused by Differential Accumulation and Ice Flow: Interpretation of a 400 Mhz Short-Pulse Radar Profile from West Antarctica |
title_fullStr |
Stratigraphic Variation Within Polar Firn Caused by Differential Accumulation and Ice Flow: Interpretation of a 400 Mhz Short-Pulse Radar Profile from West Antarctica |
title_full_unstemmed |
Stratigraphic Variation Within Polar Firn Caused by Differential Accumulation and Ice Flow: Interpretation of a 400 Mhz Short-Pulse Radar Profile from West Antarctica |
title_sort |
stratigraphic variation within polar firn caused by differential accumulation and ice flow: interpretation of a 400 mhz short-pulse radar profile from west antarctica |
publisher |
DigitalCommons@UMaine |
publishDate |
2005 |
url |
https://digitalcommons.library.umaine.edu/ers_facpub/90 https://doi.org/10.3189/172756505781829151 https://digitalcommons.library.umaine.edu/context/ers_facpub/article/1089/viewcontent/hamilton_51.174.407.pdf |
genre |
Antarc* Antarctica West Antarctica |
genre_facet |
Antarc* Antarctica West Antarctica |
op_source |
Earth Science Faculty Scholarship |
op_relation |
https://digitalcommons.library.umaine.edu/ers_facpub/90 doi:10.3189/172756505781829151 https://digitalcommons.library.umaine.edu/context/ers_facpub/article/1089/viewcontent/hamilton_51.174.407.pdf |
op_rights |
This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. In addition, no permission is required from the rights-holder(s) for educational uses. For other uses, you need to obtain permission from the rights-holder(s). |
op_doi |
https://doi.org/10.3189/172756505781829151 |
container_title |
Journal of Glaciology |
container_volume |
51 |
container_issue |
174 |
container_start_page |
407 |
op_container_end_page |
422 |
_version_ |
1810490964142194688 |