Localized uplift of Vatnajökull, Iceland

Subglacial water accumulation deduced from InSAR and GPS observations

Eyjólfur Magnússon, Helgi Björnsson, Helmut Rott, Matthew J. Roberts, Finnur Pálsson, Sverrir Gudmundsson, Richard A Bennett, Halldór Geirsson, Erik Sturkell

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

We report on satellite and ground-based observations that link glacier motion with subglacial hydrology beneath Skeidarárjökull, an outlet glacier of Vatnajökull, Iceland. We have developed a technique that uses interferometric synthetic aperture radar (InSAR) data, from the European Remote-sensing Satellite (ERS-1/-2) tandem mission (1995-2000), to detect localized anomalies in vertical ice motion. Applying this technique we identify an area of the glacier where these anomalies are frequent: above the subglacial course of the river Skeidará, where we observed uplift of 0.15-0.20md-1 during a rainstorm and a jökulhlaup, and subsidence at a slower rate subsequent to rainstorms. A similar pattern of motion is apparent from continuous GPS measurements obtained at this location in 2006/07. We argue that transient uplift of the ice surface is caused by water accumulating at the glacier base upstream of an adverse bed slope where the overburden pressure decreases significantly over a short distance. Most of the frictional energy of the flowing water is therefore needed to maintain water temperature at the pressure-melting point. Hence, little energy is available to enlarge water channels sufficiently by melting to accommodate sudden influxes of water to the base. This causes water pressure to exceed the overburden pressure, enabling uplift to occur.

Original languageEnglish (US)
Pages (from-to)475-484
Number of pages10
JournalJournal of Glaciology
Volume57
Issue number203
DOIs
StatePublished - Aug 2011

Fingerprint

glacier
synthetic aperture radar
GPS
uplift
rainstorm
overburden
melting
anomaly
ice
water
energy
hydrology
subsidence
water temperature
remote sensing
river

ASJC Scopus subject areas

  • Earth-Surface Processes

Cite this

Magnússon, E., Björnsson, H., Rott, H., Roberts, M. J., Pálsson, F., Gudmundsson, S., ... Sturkell, E. (2011). Localized uplift of Vatnajökull, Iceland: Subglacial water accumulation deduced from InSAR and GPS observations. Journal of Glaciology, 57(203), 475-484. https://doi.org/10.3189/002214311796905703

Localized uplift of Vatnajökull, Iceland : Subglacial water accumulation deduced from InSAR and GPS observations. / Magnússon, Eyjólfur; Björnsson, Helgi; Rott, Helmut; Roberts, Matthew J.; Pálsson, Finnur; Gudmundsson, Sverrir; Bennett, Richard A; Geirsson, Halldór; Sturkell, Erik.

In: Journal of Glaciology, Vol. 57, No. 203, 08.2011, p. 475-484.

Research output: Contribution to journalArticle

Magnússon, E, Björnsson, H, Rott, H, Roberts, MJ, Pálsson, F, Gudmundsson, S, Bennett, RA, Geirsson, H & Sturkell, E 2011, 'Localized uplift of Vatnajökull, Iceland: Subglacial water accumulation deduced from InSAR and GPS observations', Journal of Glaciology, vol. 57, no. 203, pp. 475-484. https://doi.org/10.3189/002214311796905703
Magnússon, Eyjólfur ; Björnsson, Helgi ; Rott, Helmut ; Roberts, Matthew J. ; Pálsson, Finnur ; Gudmundsson, Sverrir ; Bennett, Richard A ; Geirsson, Halldór ; Sturkell, Erik. / Localized uplift of Vatnajökull, Iceland : Subglacial water accumulation deduced from InSAR and GPS observations. In: Journal of Glaciology. 2011 ; Vol. 57, No. 203. pp. 475-484.
@article{903efaf8b3354b88baf6ed798513721b,
title = "Localized uplift of Vatnaj{\"o}kull, Iceland: Subglacial water accumulation deduced from InSAR and GPS observations",
abstract = "We report on satellite and ground-based observations that link glacier motion with subglacial hydrology beneath Skeidar{\'a}rj{\"o}kull, an outlet glacier of Vatnaj{\"o}kull, Iceland. We have developed a technique that uses interferometric synthetic aperture radar (InSAR) data, from the European Remote-sensing Satellite (ERS-1/-2) tandem mission (1995-2000), to detect localized anomalies in vertical ice motion. Applying this technique we identify an area of the glacier where these anomalies are frequent: above the subglacial course of the river Skeidar{\'a}, where we observed uplift of 0.15-0.20md-1 during a rainstorm and a j{\"o}kulhlaup, and subsidence at a slower rate subsequent to rainstorms. A similar pattern of motion is apparent from continuous GPS measurements obtained at this location in 2006/07. We argue that transient uplift of the ice surface is caused by water accumulating at the glacier base upstream of an adverse bed slope where the overburden pressure decreases significantly over a short distance. Most of the frictional energy of the flowing water is therefore needed to maintain water temperature at the pressure-melting point. Hence, little energy is available to enlarge water channels sufficiently by melting to accommodate sudden influxes of water to the base. This causes water pressure to exceed the overburden pressure, enabling uplift to occur.",
author = "Eyj{\'o}lfur Magn{\'u}sson and Helgi Bj{\"o}rnsson and Helmut Rott and Roberts, {Matthew J.} and Finnur P{\'a}lsson and Sverrir Gudmundsson and Bennett, {Richard A} and Halld{\'o}r Geirsson and Erik Sturkell",
year = "2011",
month = "8",
doi = "10.3189/002214311796905703",
language = "English (US)",
volume = "57",
pages = "475--484",
journal = "Journal of Glaciology",
issn = "0022-1430",
publisher = "International Glaciology Society",
number = "203",

}

TY - JOUR

T1 - Localized uplift of Vatnajökull, Iceland

T2 - Subglacial water accumulation deduced from InSAR and GPS observations

AU - Magnússon, Eyjólfur

AU - Björnsson, Helgi

AU - Rott, Helmut

AU - Roberts, Matthew J.

AU - Pálsson, Finnur

AU - Gudmundsson, Sverrir

AU - Bennett, Richard A

AU - Geirsson, Halldór

AU - Sturkell, Erik

PY - 2011/8

Y1 - 2011/8

N2 - We report on satellite and ground-based observations that link glacier motion with subglacial hydrology beneath Skeidarárjökull, an outlet glacier of Vatnajökull, Iceland. We have developed a technique that uses interferometric synthetic aperture radar (InSAR) data, from the European Remote-sensing Satellite (ERS-1/-2) tandem mission (1995-2000), to detect localized anomalies in vertical ice motion. Applying this technique we identify an area of the glacier where these anomalies are frequent: above the subglacial course of the river Skeidará, where we observed uplift of 0.15-0.20md-1 during a rainstorm and a jökulhlaup, and subsidence at a slower rate subsequent to rainstorms. A similar pattern of motion is apparent from continuous GPS measurements obtained at this location in 2006/07. We argue that transient uplift of the ice surface is caused by water accumulating at the glacier base upstream of an adverse bed slope where the overburden pressure decreases significantly over a short distance. Most of the frictional energy of the flowing water is therefore needed to maintain water temperature at the pressure-melting point. Hence, little energy is available to enlarge water channels sufficiently by melting to accommodate sudden influxes of water to the base. This causes water pressure to exceed the overburden pressure, enabling uplift to occur.

AB - We report on satellite and ground-based observations that link glacier motion with subglacial hydrology beneath Skeidarárjökull, an outlet glacier of Vatnajökull, Iceland. We have developed a technique that uses interferometric synthetic aperture radar (InSAR) data, from the European Remote-sensing Satellite (ERS-1/-2) tandem mission (1995-2000), to detect localized anomalies in vertical ice motion. Applying this technique we identify an area of the glacier where these anomalies are frequent: above the subglacial course of the river Skeidará, where we observed uplift of 0.15-0.20md-1 during a rainstorm and a jökulhlaup, and subsidence at a slower rate subsequent to rainstorms. A similar pattern of motion is apparent from continuous GPS measurements obtained at this location in 2006/07. We argue that transient uplift of the ice surface is caused by water accumulating at the glacier base upstream of an adverse bed slope where the overburden pressure decreases significantly over a short distance. Most of the frictional energy of the flowing water is therefore needed to maintain water temperature at the pressure-melting point. Hence, little energy is available to enlarge water channels sufficiently by melting to accommodate sudden influxes of water to the base. This causes water pressure to exceed the overburden pressure, enabling uplift to occur.

UR - http://www.scopus.com/inward/record.url?scp=80051907325&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80051907325&partnerID=8YFLogxK

U2 - 10.3189/002214311796905703

DO - 10.3189/002214311796905703

M3 - Article

VL - 57

SP - 475

EP - 484

JO - Journal of Glaciology

JF - Journal of Glaciology

SN - 0022-1430

IS - 203

ER -