Early melt season velocity fields of Langjökull and Hofsjökull, central Iceland
We infer the horizontal velocity fields of the ice caps Langjökull and Hofsjökull, central Iceland, using repeat-pass interferometric synthetic aperture radar (InSAR). NASA's uninhabited aerial vehicle synthetic aperture radar (UAVSAR) acquired airborne InSAR data from multiple vantage points...
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ftcaltechauth:oai:authors.library.caltech.edu:ev1ez-n2a56 2024-10-13T14:07:27+00:00 Early melt season velocity fields of Langjökull and Hofsjökull, central Iceland Minchew, Brent Simons, Mark Hensley, Scott Björnsson, Helgi Pálsson, Finnur 2015 https://doi.org/10.3189/2015JoG14J023 unknown Cambridge University Press https://doi.org/10.3189/2015JoG14J023 eprintid:87671 info:eu-repo/semantics/openAccess Other Journal of Glaciology, 61(226), 253-266, (2015) glacier flow glaciological instruments and methods ice cap ice velocity remote sensing info:eu-repo/semantics/article 2015 ftcaltechauth https://doi.org/10.3189/2015JoG14J023 2024-09-25T18:46:37Z We infer the horizontal velocity fields of the ice caps Langjökull and Hofsjökull, central Iceland, using repeat-pass interferometric synthetic aperture radar (InSAR). NASA's uninhabited aerial vehicle synthetic aperture radar (UAVSAR) acquired airborne InSAR data from multiple vantage points during the early melt season in June 2012. We develop a Bayesian approach for inferring three-dimensional velocity fields from multiple InSAR acquisitions. The horizontal components generally agree with available GPS measurements wherever ice motion is well constrained by InSAR observations. We provide evidence that changes in volumetric moisture content near the glacier surface induce phase offsets that obfuscate the vertical component of the surface velocity fields, an effect that could manifest itself on any glacier that experiences surface melt. Spatial patterns in the InSAR-derived horizontal speeds are broadly consistent with the results of a simple viscous flow model, and the directionality of the InSAR-derived horizontal flow field is nearly everywhere consistent with the ice surface gradient. Significant differences between the InSAR-derived horizontal speed and the speed predicted by the viscous flow model suggest that basal slip accounts for more than half the observed outlet glacier flow. © 2015 International Glaciological Society. MS received 25 January 2014 and accepted in revised form 30 November 2014. Published online: 10 July 2017. Funding for the UAVSAR campaign was provided by NASA's Cryospheric Sciences Program. B.M. was supported by a NASA Earth and Space Sciences fellowship and an ARCS Foundation fellowship. We thank the UAVSAR team and the NASA-Dryden flight crew who collected and helped process the InSAR data, T. Jóhannesson for providing the Hofsjökull surface DEM, S. Owen for assistance with GIPSY-OASIS and F. Ortega for reviewing the manuscript. Published - early_melt_season_velocity_fields_of_langjokull_and_hofsjokull_central_iceland.pdf Article in Journal/Newspaper glacier Ice cap Iceland Journal of Glaciology Caltech Authors (California Institute of Technology) Ortega ENVELOPE(-57.950,-57.950,-63.950,-63.950) Journal of Glaciology 61 226 253 266 |
institution |
Open Polar |
collection |
Caltech Authors (California Institute of Technology) |
op_collection_id |
ftcaltechauth |
language |
unknown |
topic |
glacier flow glaciological instruments and methods ice cap ice velocity remote sensing |
spellingShingle |
glacier flow glaciological instruments and methods ice cap ice velocity remote sensing Minchew, Brent Simons, Mark Hensley, Scott Björnsson, Helgi Pálsson, Finnur Early melt season velocity fields of Langjökull and Hofsjökull, central Iceland |
topic_facet |
glacier flow glaciological instruments and methods ice cap ice velocity remote sensing |
description |
We infer the horizontal velocity fields of the ice caps Langjökull and Hofsjökull, central Iceland, using repeat-pass interferometric synthetic aperture radar (InSAR). NASA's uninhabited aerial vehicle synthetic aperture radar (UAVSAR) acquired airborne InSAR data from multiple vantage points during the early melt season in June 2012. We develop a Bayesian approach for inferring three-dimensional velocity fields from multiple InSAR acquisitions. The horizontal components generally agree with available GPS measurements wherever ice motion is well constrained by InSAR observations. We provide evidence that changes in volumetric moisture content near the glacier surface induce phase offsets that obfuscate the vertical component of the surface velocity fields, an effect that could manifest itself on any glacier that experiences surface melt. Spatial patterns in the InSAR-derived horizontal speeds are broadly consistent with the results of a simple viscous flow model, and the directionality of the InSAR-derived horizontal flow field is nearly everywhere consistent with the ice surface gradient. Significant differences between the InSAR-derived horizontal speed and the speed predicted by the viscous flow model suggest that basal slip accounts for more than half the observed outlet glacier flow. © 2015 International Glaciological Society. MS received 25 January 2014 and accepted in revised form 30 November 2014. Published online: 10 July 2017. Funding for the UAVSAR campaign was provided by NASA's Cryospheric Sciences Program. B.M. was supported by a NASA Earth and Space Sciences fellowship and an ARCS Foundation fellowship. We thank the UAVSAR team and the NASA-Dryden flight crew who collected and helped process the InSAR data, T. Jóhannesson for providing the Hofsjökull surface DEM, S. Owen for assistance with GIPSY-OASIS and F. Ortega for reviewing the manuscript. Published - early_melt_season_velocity_fields_of_langjokull_and_hofsjokull_central_iceland.pdf |
format |
Article in Journal/Newspaper |
author |
Minchew, Brent Simons, Mark Hensley, Scott Björnsson, Helgi Pálsson, Finnur |
author_facet |
Minchew, Brent Simons, Mark Hensley, Scott Björnsson, Helgi Pálsson, Finnur |
author_sort |
Minchew, Brent |
title |
Early melt season velocity fields of Langjökull and Hofsjökull, central Iceland |
title_short |
Early melt season velocity fields of Langjökull and Hofsjökull, central Iceland |
title_full |
Early melt season velocity fields of Langjökull and Hofsjökull, central Iceland |
title_fullStr |
Early melt season velocity fields of Langjökull and Hofsjökull, central Iceland |
title_full_unstemmed |
Early melt season velocity fields of Langjökull and Hofsjökull, central Iceland |
title_sort |
early melt season velocity fields of langjã¶kull and hofsjã¶kull, central iceland |
publisher |
Cambridge University Press |
publishDate |
2015 |
url |
https://doi.org/10.3189/2015JoG14J023 |
long_lat |
ENVELOPE(-57.950,-57.950,-63.950,-63.950) |
geographic |
Ortega |
geographic_facet |
Ortega |
genre |
glacier Ice cap Iceland Journal of Glaciology |
genre_facet |
glacier Ice cap Iceland Journal of Glaciology |
op_source |
Journal of Glaciology, 61(226), 253-266, (2015) |
op_relation |
https://doi.org/10.3189/2015JoG14J023 eprintid:87671 |
op_rights |
info:eu-repo/semantics/openAccess Other |
op_doi |
https://doi.org/10.3189/2015JoG14J023 |
container_title |
Journal of Glaciology |
container_volume |
61 |
container_issue |
226 |
container_start_page |
253 |
op_container_end_page |
266 |
_version_ |
1812813750019817472 |