The 20th century retreat of ice caps in Iceland derived from airborne SAR: W-Vatnajökull and N-Mýrdalsjökull

Eyjólfur Magnússon; Helgi Björnsson; Jørgen Dall; Finnur Pálsson

doi:10.1016/j.epsl.2005.06.038

The 20th century retreat of ice caps in Iceland derived from airborne SAR: W-Vatnajökull and N-Mýrdalsjökull

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Abstract

We present observations of the long-term recession of surging outlets of Icelandic ice caps in response to 20th century climate. In August 1998, synthetic aperture radar (SAR) data, covering the western part of Vatnajökull and the northern part of Mýrdalsjökull in southern Iceland, were acquired with the Danish airborne EMISAR radar system. Polarimetric and interferometric SAR data reveal the margins of the present ice caps as well as a series of terminal moraines in the fore field. These moraines date back to the maximum Neoglacial extent at the end of the 19th century and the outermost allow reconstruction of the margin at that time. The data offer a unique opportunity to estimate the area decrease of these ice caps in the 20th century. The influence of the fluctuations of the surge type outlets, constituting most of W-Vatnajökull area and a good part of N-Mýrdalsjökull area, is minimal, since they had all recently surged in 1998 as was presumably the case when the outermost moraines were formed. The major contributor to the area decrease is therefore climate changes in the 20th century even though the glacier retreat has been interrupted by short-lived surges. Moraines associated with most of the surges in W-Vatnajökull in the 20th century are observed in the SAR data including the most recent surges in the 1990s. Interestingly no push moraines were observed in front of the surge advance, but the moraines appear when the glaciers start retreating. We estimate that the collective decrease of the outlets of western Vatnajökull since maximum Neoglacial extent of each outlet, is 109 km² (6.7%) corresponding to an average retreat of 850 m over a 130 km long margin. In the same period the outlet Sléttjökull, in N-Mýrdalsjökull, has decreased by 33 km² (20%) corresponding to an average retreat of 1500 m over a 20 km long margin.

Original language	English
Pages (from-to)	508-515
Number of pages	8
Journal	Earth and Planetary Science Letters
Volume	237
Issue number	3-4
DOIs	https://doi.org/10.1016/j.epsl.2005.06.038
Publication status	Published - 15 Sept 2005

Bibliographical note

Funding Information: This work is a part of Eyjólfur Magnússon's Master thesis, which the Icelandic Centre for Research, the Science Institute, University of Iceland and the Southern Region Institute for Advanced Learning have supported by research grants. The EMISAR system was flown on a Gulfstream Jet from the Royal Danish Air Force, and the data acquisition was financed by the Danish National Research Foundation. The processing of the SAR data was financed by the Science Institute, University of Iceland, the National Land Survey of Iceland, the Soil Conservation Service of Iceland, the Agricultural Research Institute, the Icelandic Museum of Natural History, the National Power Company, the Nordic Volcanological Institute, the National Energy Authority and the South Iceland Forestry. We thank Steen Stavstrup Kristensen at Electromagnetic Systems, Technical University of Denmark, for processing the polarimetric data as well as Wolfgang Dierking and Henning Skriver, also at ES, for their help in the coregistration of the polarimetric data with the DEM.

Other keywords

Glacier changes
PolSAR
SAR
Terminal moraines

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10.1016/j.epsl.2005.06.038

Cite this

@article{5e77429c461f4dc289f430ca8e4b63c1,

title = "The 20th century retreat of ice caps in Iceland derived from airborne SAR: W-Vatnaj{\"o}kull and N-M{\'y}rdalsj{\"o}kull",

abstract = "We present observations of the long-term recession of surging outlets of Icelandic ice caps in response to 20th century climate. In August 1998, synthetic aperture radar (SAR) data, covering the western part of Vatnaj{\"o}kull and the northern part of M{\'y}rdalsj{\"o}kull in southern Iceland, were acquired with the Danish airborne EMISAR radar system. Polarimetric and interferometric SAR data reveal the margins of the present ice caps as well as a series of terminal moraines in the fore field. These moraines date back to the maximum Neoglacial extent at the end of the 19th century and the outermost allow reconstruction of the margin at that time. The data offer a unique opportunity to estimate the area decrease of these ice caps in the 20th century. The influence of the fluctuations of the surge type outlets, constituting most of W-Vatnaj{\"o}kull area and a good part of N-M{\'y}rdalsj{\"o}kull area, is minimal, since they had all recently surged in 1998 as was presumably the case when the outermost moraines were formed. The major contributor to the area decrease is therefore climate changes in the 20th century even though the glacier retreat has been interrupted by short-lived surges. Moraines associated with most of the surges in W-Vatnaj{\"o}kull in the 20th century are observed in the SAR data including the most recent surges in the 1990s. Interestingly no push moraines were observed in front of the surge advance, but the moraines appear when the glaciers start retreating. We estimate that the collective decrease of the outlets of western Vatnaj{\"o}kull since maximum Neoglacial extent of each outlet, is 109 km2 (6.7\%) corresponding to an average retreat of 850 m over a 130 km long margin. In the same period the outlet Sl{\'e}ttj{\"o}kull, in N-M{\'y}rdalsj{\"o}kull, has decreased by 33 km2 (20\%) corresponding to an average retreat of 1500 m over a 20 km long margin.",

keywords = "Glacier changes, PolSAR, SAR, Terminal moraines",

author = "Eyj{\'o}lfur Magn{\'u}sson and Helgi Bj{\"o}rnsson and J{\o}rgen Dall and Finnur P{\'a}lsson",

note = "Funding Information: This work is a part of Eyj{\'o}lfur Magn{\'u}sson's Master thesis, which the Icelandic Centre for Research, the Science Institute, University of Iceland and the Southern Region Institute for Advanced Learning have supported by research grants. The EMISAR system was flown on a Gulfstream Jet from the Royal Danish Air Force, and the data acquisition was financed by the Danish National Research Foundation. The processing of the SAR data was financed by the Science Institute, University of Iceland, the National Land Survey of Iceland, the Soil Conservation Service of Iceland, the Agricultural Research Institute, the Icelandic Museum of Natural History, the National Power Company, the Nordic Volcanological Institute, the National Energy Authority and the South Iceland Forestry. We thank Steen Stavstrup Kristensen at Electromagnetic Systems, Technical University of Denmark, for processing the polarimetric data as well as Wolfgang Dierking and Henning Skriver, also at ES, for their help in the coregistration of the polarimetric data with the DEM.",

year = "2005",

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doi = "10.1016/j.epsl.2005.06.038",

language = "English",

volume = "237",

pages = "508--515",

journal = "Earth and Planetary Science Letters",

issn = "0012-821X",

publisher = "Elsevier B.V.",

number = "3-4",

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TY - JOUR

T1 - The 20th century retreat of ice caps in Iceland derived from airborne SAR

T2 - W-Vatnajökull and N-Mýrdalsjökull

AU - Magnússon, Eyjólfur

AU - Björnsson, Helgi

AU - Dall, Jørgen

AU - Pálsson, Finnur

N1 - Funding Information: This work is a part of Eyjólfur Magnússon's Master thesis, which the Icelandic Centre for Research, the Science Institute, University of Iceland and the Southern Region Institute for Advanced Learning have supported by research grants. The EMISAR system was flown on a Gulfstream Jet from the Royal Danish Air Force, and the data acquisition was financed by the Danish National Research Foundation. The processing of the SAR data was financed by the Science Institute, University of Iceland, the National Land Survey of Iceland, the Soil Conservation Service of Iceland, the Agricultural Research Institute, the Icelandic Museum of Natural History, the National Power Company, the Nordic Volcanological Institute, the National Energy Authority and the South Iceland Forestry. We thank Steen Stavstrup Kristensen at Electromagnetic Systems, Technical University of Denmark, for processing the polarimetric data as well as Wolfgang Dierking and Henning Skriver, also at ES, for their help in the coregistration of the polarimetric data with the DEM.

PY - 2005/9/15

Y1 - 2005/9/15

N2 - We present observations of the long-term recession of surging outlets of Icelandic ice caps in response to 20th century climate. In August 1998, synthetic aperture radar (SAR) data, covering the western part of Vatnajökull and the northern part of Mýrdalsjökull in southern Iceland, were acquired with the Danish airborne EMISAR radar system. Polarimetric and interferometric SAR data reveal the margins of the present ice caps as well as a series of terminal moraines in the fore field. These moraines date back to the maximum Neoglacial extent at the end of the 19th century and the outermost allow reconstruction of the margin at that time. The data offer a unique opportunity to estimate the area decrease of these ice caps in the 20th century. The influence of the fluctuations of the surge type outlets, constituting most of W-Vatnajökull area and a good part of N-Mýrdalsjökull area, is minimal, since they had all recently surged in 1998 as was presumably the case when the outermost moraines were formed. The major contributor to the area decrease is therefore climate changes in the 20th century even though the glacier retreat has been interrupted by short-lived surges. Moraines associated with most of the surges in W-Vatnajökull in the 20th century are observed in the SAR data including the most recent surges in the 1990s. Interestingly no push moraines were observed in front of the surge advance, but the moraines appear when the glaciers start retreating. We estimate that the collective decrease of the outlets of western Vatnajökull since maximum Neoglacial extent of each outlet, is 109 km2 (6.7%) corresponding to an average retreat of 850 m over a 130 km long margin. In the same period the outlet Sléttjökull, in N-Mýrdalsjökull, has decreased by 33 km2 (20%) corresponding to an average retreat of 1500 m over a 20 km long margin.

AB - We present observations of the long-term recession of surging outlets of Icelandic ice caps in response to 20th century climate. In August 1998, synthetic aperture radar (SAR) data, covering the western part of Vatnajökull and the northern part of Mýrdalsjökull in southern Iceland, were acquired with the Danish airborne EMISAR radar system. Polarimetric and interferometric SAR data reveal the margins of the present ice caps as well as a series of terminal moraines in the fore field. These moraines date back to the maximum Neoglacial extent at the end of the 19th century and the outermost allow reconstruction of the margin at that time. The data offer a unique opportunity to estimate the area decrease of these ice caps in the 20th century. The influence of the fluctuations of the surge type outlets, constituting most of W-Vatnajökull area and a good part of N-Mýrdalsjökull area, is minimal, since they had all recently surged in 1998 as was presumably the case when the outermost moraines were formed. The major contributor to the area decrease is therefore climate changes in the 20th century even though the glacier retreat has been interrupted by short-lived surges. Moraines associated with most of the surges in W-Vatnajökull in the 20th century are observed in the SAR data including the most recent surges in the 1990s. Interestingly no push moraines were observed in front of the surge advance, but the moraines appear when the glaciers start retreating. We estimate that the collective decrease of the outlets of western Vatnajökull since maximum Neoglacial extent of each outlet, is 109 km2 (6.7%) corresponding to an average retreat of 850 m over a 130 km long margin. In the same period the outlet Sléttjökull, in N-Mýrdalsjökull, has decreased by 33 km2 (20%) corresponding to an average retreat of 1500 m over a 20 km long margin.

KW - Glacier changes

KW - PolSAR

KW - SAR

KW - Terminal moraines

UR - https://www.scopus.com/pages/publications/24144463951

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DO - 10.1016/j.epsl.2005.06.038

M3 - Article

SN - 0012-821X

VL - 237

SP - 508

EP - 515

JO - Earth and Planetary Science Letters

JF - Earth and Planetary Science Letters

IS - 3-4

ER -

The 20th century retreat of ice caps in Iceland derived from airborne SAR: W-Vatnajökull and N-Mýrdalsjökull

Abstract

Bibliographical note

Other keywords

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