Estimation of PGR Induced Absolute Gravity Changes at Greenland GNET Stations

Research output: Chapter in Book/Report/Conference proceedingBook chapterResearchpeer-review

Abstract

An important subject in the climate debate is the study of the major ice sheets mass balance. Knowledge of the mass balance provides understanding of changes in the relative sea-level (RSL). Several methods are used for mass balance studies but they are associated with large uncertainties. One reason for the uncertainty is the presence of the postglacial rebound (PGR) signal in the geodetic data used for mass balance estimates. Estimates of the PGR signal can be obtained by modelling and then being subtracted from the data to eliminate its influence. In this study, the PGR gravity signal will be investigated through modelling. The modelling of seven different scenarios shows that the PGR gravity signal in Greenland is less then 1 mu Gal/year (1 mu Gal=10 nm/s(2)). Repeated absolute gravity (AG) measurements at selected Greenland network (GNET) GPS sites were initiated in 2009. These data will in the future help constrain PGR and present-day ice mass changes. The data is collected with an A10 absolute gravimeter, which has an accuracy of 10 mu Gal (manufacturer specification). Here we will evaluate themodelled PGR gravity signal at selected GNET sites and conclude that the signal is significantly smaller then the gravity instruments accuracy and a long time is needed to detect it. Also, it can be expected that the elastic signal will be larger and other data like GPS is needed to separate the viscous and elastic signal.
Original languageEnglish
Title of host publicationEarth on the Edge: Science for a Sustainable Planet : Proceedings of the IAG General Assembly, Melbourne, Australia, June 28 - July 2, 2011
Editors Chris Rizos , Pascal Willis
Volume139; Book Part II
PublisherSpringer
Publication date2014
Pages97-102
ISBN (Print)978-3-642-37221-6
ISBN (Electronic)978-3-642-37222-3
DOIs
Publication statusPublished - 2014
Event2011 IAG General Assembly - Melbourne Convention and Exhibition Centre, Melbourne, Australia
Duration: 28 Jun 20117 Jul 2011

Conference

Conference2011 IAG General Assembly
LocationMelbourne Convention and Exhibition Centre
CountryAustralia
CityMelbourne
Period28/06/201107/07/2011
SeriesInternational Association of Geodesy Symposia
ISSN0939-9585

Keywords

  • Greenland
  • Postglacial rebound
  • Absolute gravity

Cite this

Nielsen, E., Strykowski, G., Forsberg, R., & Madsen, F. B. (2014). Estimation of PGR Induced Absolute Gravity Changes at Greenland GNET Stations. In C. Rizos , & P. Willis (Eds.), Earth on the Edge: Science for a Sustainable Planet: Proceedings of the IAG General Assembly, Melbourne, Australia, June 28 - July 2, 2011 (Vol. 139; Book Part II, pp. 97-102). Springer. International Association of Geodesy Symposia https://doi.org/10.1007/978-3-642-37222-3_12
Nielsen, Emil ; Strykowski, Gabriel ; Forsberg, René ; Madsen, Finn Bo. / Estimation of PGR Induced Absolute Gravity Changes at Greenland GNET Stations. Earth on the Edge: Science for a Sustainable Planet: Proceedings of the IAG General Assembly, Melbourne, Australia, June 28 - July 2, 2011. editor / Chris Rizos ; Pascal Willis. Vol. 139; Book Part II Springer, 2014. pp. 97-102 (International Association of Geodesy Symposia).
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abstract = "An important subject in the climate debate is the study of the major ice sheets mass balance. Knowledge of the mass balance provides understanding of changes in the relative sea-level (RSL). Several methods are used for mass balance studies but they are associated with large uncertainties. One reason for the uncertainty is the presence of the postglacial rebound (PGR) signal in the geodetic data used for mass balance estimates. Estimates of the PGR signal can be obtained by modelling and then being subtracted from the data to eliminate its influence. In this study, the PGR gravity signal will be investigated through modelling. The modelling of seven different scenarios shows that the PGR gravity signal in Greenland is less then 1 mu Gal/year (1 mu Gal=10 nm/s(2)). Repeated absolute gravity (AG) measurements at selected Greenland network (GNET) GPS sites were initiated in 2009. These data will in the future help constrain PGR and present-day ice mass changes. The data is collected with an A10 absolute gravimeter, which has an accuracy of 10 mu Gal (manufacturer specification). Here we will evaluate themodelled PGR gravity signal at selected GNET sites and conclude that the signal is significantly smaller then the gravity instruments accuracy and a long time is needed to detect it. Also, it can be expected that the elastic signal will be larger and other data like GPS is needed to separate the viscous and elastic signal.",
keywords = "Greenland, Postglacial rebound, Absolute gravity",
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Nielsen, E, Strykowski, G, Forsberg, R & Madsen, FB 2014, Estimation of PGR Induced Absolute Gravity Changes at Greenland GNET Stations. in C Rizos & P Willis (eds), Earth on the Edge: Science for a Sustainable Planet: Proceedings of the IAG General Assembly, Melbourne, Australia, June 28 - July 2, 2011. vol. 139; Book Part II, Springer, International Association of Geodesy Symposia, pp. 97-102, 2011 IAG General Assembly, Melbourne, Australia, 28/06/2011. https://doi.org/10.1007/978-3-642-37222-3_12

Estimation of PGR Induced Absolute Gravity Changes at Greenland GNET Stations. / Nielsen, Emil; Strykowski, Gabriel; Forsberg, René; Madsen, Finn Bo.

Earth on the Edge: Science for a Sustainable Planet: Proceedings of the IAG General Assembly, Melbourne, Australia, June 28 - July 2, 2011. ed. / Chris Rizos ; Pascal Willis. Vol. 139; Book Part II Springer, 2014. p. 97-102 (International Association of Geodesy Symposia).

Research output: Chapter in Book/Report/Conference proceedingBook chapterResearchpeer-review

TY - CHAP

T1 - Estimation of PGR Induced Absolute Gravity Changes at Greenland GNET Stations

AU - Nielsen, Emil

AU - Strykowski, Gabriel

AU - Forsberg, René

AU - Madsen, Finn Bo

PY - 2014

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N2 - An important subject in the climate debate is the study of the major ice sheets mass balance. Knowledge of the mass balance provides understanding of changes in the relative sea-level (RSL). Several methods are used for mass balance studies but they are associated with large uncertainties. One reason for the uncertainty is the presence of the postglacial rebound (PGR) signal in the geodetic data used for mass balance estimates. Estimates of the PGR signal can be obtained by modelling and then being subtracted from the data to eliminate its influence. In this study, the PGR gravity signal will be investigated through modelling. The modelling of seven different scenarios shows that the PGR gravity signal in Greenland is less then 1 mu Gal/year (1 mu Gal=10 nm/s(2)). Repeated absolute gravity (AG) measurements at selected Greenland network (GNET) GPS sites were initiated in 2009. These data will in the future help constrain PGR and present-day ice mass changes. The data is collected with an A10 absolute gravimeter, which has an accuracy of 10 mu Gal (manufacturer specification). Here we will evaluate themodelled PGR gravity signal at selected GNET sites and conclude that the signal is significantly smaller then the gravity instruments accuracy and a long time is needed to detect it. Also, it can be expected that the elastic signal will be larger and other data like GPS is needed to separate the viscous and elastic signal.

AB - An important subject in the climate debate is the study of the major ice sheets mass balance. Knowledge of the mass balance provides understanding of changes in the relative sea-level (RSL). Several methods are used for mass balance studies but they are associated with large uncertainties. One reason for the uncertainty is the presence of the postglacial rebound (PGR) signal in the geodetic data used for mass balance estimates. Estimates of the PGR signal can be obtained by modelling and then being subtracted from the data to eliminate its influence. In this study, the PGR gravity signal will be investigated through modelling. The modelling of seven different scenarios shows that the PGR gravity signal in Greenland is less then 1 mu Gal/year (1 mu Gal=10 nm/s(2)). Repeated absolute gravity (AG) measurements at selected Greenland network (GNET) GPS sites were initiated in 2009. These data will in the future help constrain PGR and present-day ice mass changes. The data is collected with an A10 absolute gravimeter, which has an accuracy of 10 mu Gal (manufacturer specification). Here we will evaluate themodelled PGR gravity signal at selected GNET sites and conclude that the signal is significantly smaller then the gravity instruments accuracy and a long time is needed to detect it. Also, it can be expected that the elastic signal will be larger and other data like GPS is needed to separate the viscous and elastic signal.

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KW - Postglacial rebound

KW - Absolute gravity

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DO - 10.1007/978-3-642-37222-3_12

M3 - Book chapter

SN - 978-3-642-37221-6

VL - 139; Book Part II

T3 - International Association of Geodesy Symposia

SP - 97

EP - 102

BT - Earth on the Edge: Science for a Sustainable Planet

A2 - Rizos , Chris

A2 - Willis, Pascal

PB - Springer

ER -

Nielsen E, Strykowski G, Forsberg R, Madsen FB. Estimation of PGR Induced Absolute Gravity Changes at Greenland GNET Stations. In Rizos C, Willis P, editors, Earth on the Edge: Science for a Sustainable Planet: Proceedings of the IAG General Assembly, Melbourne, Australia, June 28 - July 2, 2011. Vol. 139; Book Part II. Springer. 2014. p. 97-102. (International Association of Geodesy Symposia). https://doi.org/10.1007/978-3-642-37222-3_12