The effect of signal leakage and glacial isostatic rebound on GRACE-derived ice mass changes in Iceland

Louise Sandberg Sørensen, Alexander H. Jarosch, Gudfinna Adalgeirsdottir, Valentina Roberta Barletta, René Forsberg, Finnur Pálsson, Helgi Bjornsson, Tomas Johannesson

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Abstract

Monthly gravity field models from the GRACE satellite mission are widely used to determine ice mass changes of large ice sheets as well as smaller glaciers and ice caps. Here, we investigate in detail the ice mass changes of the Icelandic ice caps as derived from GRACE data. The small size of the Icelandic ice caps, their location close to other rapidly changing ice covered areas and the low viscosity of the mantle below Iceland make this especially challenging. The mass balance of the ice caps is well constrained by field mass balance measurements, making this area ideal for such investigations. We find that the ice mass changes of the Icelandic ice caps derived from GRACE gravity field models are influenced by both the large gravity change signal resulting from ice mass loss in southeast Greenland and the mass redistribution within the Earth mantle due to glacial isostatic adjustment since the Little Ice Age (∼ 1890 AD). To minimize the signal that leaks towards Iceland from Greenland, we employ an independent mass change estimate of the Greenland Ice Sheet derived from satellite laser altimetry. We also estimate the effect of post Little Ice Age glacial isostatic adjustment, from knowledge of the ice history and GPS network constrained crustal deformation data. We find that both the leakage from Greenland and the post Little Ice Age glacial isostatic adjustment are important to take into account, in order to correctly determine Iceland ice mass changes from GRACE, and when applying these an average mass balance of the Icelandic ice caps of -11.4 +/- 2.2 Gt yr-1 for the period 2003-2010 is found. This number corresponds well with available mass balance measurements.
Original languageEnglish
JournalGeophysical Journal International
Volume209
Issue number1
Pages (from-to)226-233
ISSN0956-540X
DOIs
Publication statusPublished - 2017

Bibliographical note

This article has been accepted for publication inGeophysical Journal International © The Authors 2017. Published by Oxford University Press on behalf of The Royal Astronomical Society.

Keywords

  • GEOCHEMISTRY
  • TIME-VARIABLE GRAVITY
  • SEA-LEVEL RISE
  • GREENLAND
  • SURFACE
  • BALANCE
  • EARTH
  • CAPS
  • ACCELERATION
  • VARIABILITY
  • ANTARCTICA
  • Inverse theory
  • Time variable gravity
  • Global change from geodesy
  • Glaciology
  • Arctic region

Cite this

Sørensen, Louise Sandberg ; Jarosch, Alexander H. ; Adalgeirsdottir, Gudfinna ; Barletta, Valentina Roberta ; Forsberg, René ; Pálsson, Finnur ; Bjornsson, Helgi ; Johannesson, Tomas. / The effect of signal leakage and glacial isostatic rebound on GRACE-derived ice mass changes in Iceland. In: Geophysical Journal International. 2017 ; Vol. 209, No. 1. pp. 226-233.
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abstract = "Monthly gravity field models from the GRACE satellite mission are widely used to determine ice mass changes of large ice sheets as well as smaller glaciers and ice caps. Here, we investigate in detail the ice mass changes of the Icelandic ice caps as derived from GRACE data. The small size of the Icelandic ice caps, their location close to other rapidly changing ice covered areas and the low viscosity of the mantle below Iceland make this especially challenging. The mass balance of the ice caps is well constrained by field mass balance measurements, making this area ideal for such investigations. We find that the ice mass changes of the Icelandic ice caps derived from GRACE gravity field models are influenced by both the large gravity change signal resulting from ice mass loss in southeast Greenland and the mass redistribution within the Earth mantle due to glacial isostatic adjustment since the Little Ice Age (∼ 1890 AD). To minimize the signal that leaks towards Iceland from Greenland, we employ an independent mass change estimate of the Greenland Ice Sheet derived from satellite laser altimetry. We also estimate the effect of post Little Ice Age glacial isostatic adjustment, from knowledge of the ice history and GPS network constrained crustal deformation data. We find that both the leakage from Greenland and the post Little Ice Age glacial isostatic adjustment are important to take into account, in order to correctly determine Iceland ice mass changes from GRACE, and when applying these an average mass balance of the Icelandic ice caps of -11.4 +/- 2.2 Gt yr-1 for the period 2003-2010 is found. This number corresponds well with available mass balance measurements.",
keywords = "GEOCHEMISTRY, TIME-VARIABLE GRAVITY, SEA-LEVEL RISE, GREENLAND, SURFACE, BALANCE, EARTH, CAPS, ACCELERATION, VARIABILITY, ANTARCTICA, Inverse theory, Time variable gravity, Global change from geodesy, Glaciology, Arctic region",
author = "S{\o}rensen, {Louise Sandberg} and Jarosch, {Alexander H.} and Gudfinna Adalgeirsdottir and Barletta, {Valentina Roberta} and Ren{\'e} Forsberg and Finnur P{\'a}lsson and Helgi Bjornsson and Tomas Johannesson",
note = "This article has been accepted for publication inGeophysical Journal International {\circledC} The Authors 2017. Published by Oxford University Press on behalf of The Royal Astronomical Society.",
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The effect of signal leakage and glacial isostatic rebound on GRACE-derived ice mass changes in Iceland. / Sørensen, Louise Sandberg; Jarosch, Alexander H.; Adalgeirsdottir, Gudfinna; Barletta, Valentina Roberta; Forsberg, René; Pálsson, Finnur; Bjornsson, Helgi; Johannesson, Tomas.

In: Geophysical Journal International, Vol. 209, No. 1, 2017, p. 226-233.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - The effect of signal leakage and glacial isostatic rebound on GRACE-derived ice mass changes in Iceland

AU - Sørensen, Louise Sandberg

AU - Jarosch, Alexander H.

AU - Adalgeirsdottir, Gudfinna

AU - Barletta, Valentina Roberta

AU - Forsberg, René

AU - Pálsson, Finnur

AU - Bjornsson, Helgi

AU - Johannesson, Tomas

N1 - This article has been accepted for publication inGeophysical Journal International © The Authors 2017. Published by Oxford University Press on behalf of The Royal Astronomical Society.

PY - 2017

Y1 - 2017

N2 - Monthly gravity field models from the GRACE satellite mission are widely used to determine ice mass changes of large ice sheets as well as smaller glaciers and ice caps. Here, we investigate in detail the ice mass changes of the Icelandic ice caps as derived from GRACE data. The small size of the Icelandic ice caps, their location close to other rapidly changing ice covered areas and the low viscosity of the mantle below Iceland make this especially challenging. The mass balance of the ice caps is well constrained by field mass balance measurements, making this area ideal for such investigations. We find that the ice mass changes of the Icelandic ice caps derived from GRACE gravity field models are influenced by both the large gravity change signal resulting from ice mass loss in southeast Greenland and the mass redistribution within the Earth mantle due to glacial isostatic adjustment since the Little Ice Age (∼ 1890 AD). To minimize the signal that leaks towards Iceland from Greenland, we employ an independent mass change estimate of the Greenland Ice Sheet derived from satellite laser altimetry. We also estimate the effect of post Little Ice Age glacial isostatic adjustment, from knowledge of the ice history and GPS network constrained crustal deformation data. We find that both the leakage from Greenland and the post Little Ice Age glacial isostatic adjustment are important to take into account, in order to correctly determine Iceland ice mass changes from GRACE, and when applying these an average mass balance of the Icelandic ice caps of -11.4 +/- 2.2 Gt yr-1 for the period 2003-2010 is found. This number corresponds well with available mass balance measurements.

AB - Monthly gravity field models from the GRACE satellite mission are widely used to determine ice mass changes of large ice sheets as well as smaller glaciers and ice caps. Here, we investigate in detail the ice mass changes of the Icelandic ice caps as derived from GRACE data. The small size of the Icelandic ice caps, their location close to other rapidly changing ice covered areas and the low viscosity of the mantle below Iceland make this especially challenging. The mass balance of the ice caps is well constrained by field mass balance measurements, making this area ideal for such investigations. We find that the ice mass changes of the Icelandic ice caps derived from GRACE gravity field models are influenced by both the large gravity change signal resulting from ice mass loss in southeast Greenland and the mass redistribution within the Earth mantle due to glacial isostatic adjustment since the Little Ice Age (∼ 1890 AD). To minimize the signal that leaks towards Iceland from Greenland, we employ an independent mass change estimate of the Greenland Ice Sheet derived from satellite laser altimetry. We also estimate the effect of post Little Ice Age glacial isostatic adjustment, from knowledge of the ice history and GPS network constrained crustal deformation data. We find that both the leakage from Greenland and the post Little Ice Age glacial isostatic adjustment are important to take into account, in order to correctly determine Iceland ice mass changes from GRACE, and when applying these an average mass balance of the Icelandic ice caps of -11.4 +/- 2.2 Gt yr-1 for the period 2003-2010 is found. This number corresponds well with available mass balance measurements.

KW - GEOCHEMISTRY

KW - TIME-VARIABLE GRAVITY

KW - SEA-LEVEL RISE

KW - GREENLAND

KW - SURFACE

KW - BALANCE

KW - EARTH

KW - CAPS

KW - ACCELERATION

KW - VARIABILITY

KW - ANTARCTICA

KW - Inverse theory

KW - Time variable gravity

KW - Global change from geodesy

KW - Glaciology

KW - Arctic region

U2 - 10.1093/gji/ggx008

DO - 10.1093/gji/ggx008

M3 - Journal article

VL - 209

SP - 226

EP - 233

JO - Geophysical Journal International

JF - Geophysical Journal International

SN - 0956-540X

IS - 1

ER -