Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model
The Northeast Greenland Ice Stream (NEGIS) is the largest active ice stream on the Greenland Ice Sheet (GrIS) and a crucial contributor to the ice-sheet mass balance. To investigate the ice-stream dynamics and to gain information about the past climate, a deep ice core is drilled in the upstream par...
Published in: | The Cryosphere |
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Copernicus Publications on behalf of the European Geosciences Union
2021
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Online Access: | https://epic.awi.de/id/eprint/54441/ https://epic.awi.de/id/eprint/54441/1/tc-15-3655-2021.pdf https://tc.copernicus.org/articles/15/3655/2021/ https://hdl.handle.net/10013/epic.e961618f-2afa-4479-87cc-195eebd34c3b https://hdl.handle.net/ |
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ftawi:oai:epic.awi.de:54441 2023-05-15T16:03:55+02:00 Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model Gerber, Tamara Schøtt Hvidberg, Christine Olander Rasmussen, Sune Franke, Steven Sinnl, Giulia Grinsted, Aslak Jansen, Daniela Dahl-Jensen, Dorthe 2021-08-06 application/pdf https://epic.awi.de/id/eprint/54441/ https://epic.awi.de/id/eprint/54441/1/tc-15-3655-2021.pdf https://tc.copernicus.org/articles/15/3655/2021/ https://hdl.handle.net/10013/epic.e961618f-2afa-4479-87cc-195eebd34c3b https://hdl.handle.net/ unknown Copernicus Publications on behalf of the European Geosciences Union https://epic.awi.de/id/eprint/54441/1/tc-15-3655-2021.pdf https://hdl.handle.net/ Gerber, T. , Schøtt Hvidberg, C. , Olander Rasmussen, S. , Franke, S. orcid:0000-0001-8462-4379 , Sinnl, G. , Grinsted, A. , Jansen, D. orcid:0000-0002-4412-5820 and Dahl-Jensen, D. (2021) Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model , The Cryosphere, 15 (8), pp. 3655-3679 . doi:10.5194/tc-15-3655-2021 <https://doi.org/10.5194/tc-15-3655-2021> , hdl:10013/epic.e961618f-2afa-4479-87cc-195eebd34c3b EPIC3The Cryosphere, Copernicus Publications on behalf of the European Geosciences Union, 15(8), pp. 3655-3679 Article isiRev 2021 ftawi https://doi.org/10.5194/tc-15-3655-2021 2021-12-24T15:46:27Z The Northeast Greenland Ice Stream (NEGIS) is the largest active ice stream on the Greenland Ice Sheet (GrIS) and a crucial contributor to the ice-sheet mass balance. To investigate the ice-stream dynamics and to gain information about the past climate, a deep ice core is drilled in the upstream part of the NEGIS, termed the East Greenland Ice-core Project (EastGRIP). Upstream flow can introduce climatic bias into ice cores through the advection of ice deposited under different conditions further upstream. This is particularly true for EastGRIP due to its location inside an ice stream on the eastern flank of the GrIS. Understanding and ultimately correcting for such effects requires information on the atmospheric conditions at the time and location of snow deposition. We use a two-dimensional Dansgaard–Johnsen model to simulate ice flow along three approximated flow lines between the summit of the ice sheet (GRIP) and EastGRIP. Isochrones are traced in radio-echo-sounding images along these flow lines and dated with the GRIP and EastGRIP ice-core chronologies. The observed depth–age relationship constrains the Monte Carlo method which is used to determine unknown model parameters. We calculate backward-in-time particle trajectories to determine the source location of ice found in the EastGRIP ice core and present estimates of surface elevation and past accumulation rates at the deposition site. Our results indicate that increased snow accumulation with increasing upstream distance is predominantly responsible for the constant annual layer thicknesses observed in the upper part of the ice column at EastGRIP, and the inverted model parameters suggest that basal melting and sliding are important factors determining ice flow in the NEGIS. The results of this study form a basis for applying upstream corrections to a variety of ice-core measurements, and the inverted model parameters are useful constraints for more sophisticated modelling approaches in the future. Article in Journal/Newspaper East Greenland East Greenland Ice-core Project Greenland Greenland ice core Greenland Ice core Project GRIP ice core Ice Sheet The Cryosphere Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Greenland The Cryosphere 15 8 3655 3679 |
institution |
Open Polar |
collection |
Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
The Northeast Greenland Ice Stream (NEGIS) is the largest active ice stream on the Greenland Ice Sheet (GrIS) and a crucial contributor to the ice-sheet mass balance. To investigate the ice-stream dynamics and to gain information about the past climate, a deep ice core is drilled in the upstream part of the NEGIS, termed the East Greenland Ice-core Project (EastGRIP). Upstream flow can introduce climatic bias into ice cores through the advection of ice deposited under different conditions further upstream. This is particularly true for EastGRIP due to its location inside an ice stream on the eastern flank of the GrIS. Understanding and ultimately correcting for such effects requires information on the atmospheric conditions at the time and location of snow deposition. We use a two-dimensional Dansgaard–Johnsen model to simulate ice flow along three approximated flow lines between the summit of the ice sheet (GRIP) and EastGRIP. Isochrones are traced in radio-echo-sounding images along these flow lines and dated with the GRIP and EastGRIP ice-core chronologies. The observed depth–age relationship constrains the Monte Carlo method which is used to determine unknown model parameters. We calculate backward-in-time particle trajectories to determine the source location of ice found in the EastGRIP ice core and present estimates of surface elevation and past accumulation rates at the deposition site. Our results indicate that increased snow accumulation with increasing upstream distance is predominantly responsible for the constant annual layer thicknesses observed in the upper part of the ice column at EastGRIP, and the inverted model parameters suggest that basal melting and sliding are important factors determining ice flow in the NEGIS. The results of this study form a basis for applying upstream corrections to a variety of ice-core measurements, and the inverted model parameters are useful constraints for more sophisticated modelling approaches in the future. |
format |
Article in Journal/Newspaper |
author |
Gerber, Tamara Schøtt Hvidberg, Christine Olander Rasmussen, Sune Franke, Steven Sinnl, Giulia Grinsted, Aslak Jansen, Daniela Dahl-Jensen, Dorthe |
spellingShingle |
Gerber, Tamara Schøtt Hvidberg, Christine Olander Rasmussen, Sune Franke, Steven Sinnl, Giulia Grinsted, Aslak Jansen, Daniela Dahl-Jensen, Dorthe Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model |
author_facet |
Gerber, Tamara Schøtt Hvidberg, Christine Olander Rasmussen, Sune Franke, Steven Sinnl, Giulia Grinsted, Aslak Jansen, Daniela Dahl-Jensen, Dorthe |
author_sort |
Gerber, Tamara |
title |
Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model |
title_short |
Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model |
title_full |
Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model |
title_fullStr |
Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model |
title_full_unstemmed |
Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model |
title_sort |
upstream flow effects revealed in the eastgrip ice core using monte carlo inversion of a two-dimensional ice-flow model |
publisher |
Copernicus Publications on behalf of the European Geosciences Union |
publishDate |
2021 |
url |
https://epic.awi.de/id/eprint/54441/ https://epic.awi.de/id/eprint/54441/1/tc-15-3655-2021.pdf https://tc.copernicus.org/articles/15/3655/2021/ https://hdl.handle.net/10013/epic.e961618f-2afa-4479-87cc-195eebd34c3b https://hdl.handle.net/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
East Greenland East Greenland Ice-core Project Greenland Greenland ice core Greenland Ice core Project GRIP ice core Ice Sheet The Cryosphere |
genre_facet |
East Greenland East Greenland Ice-core Project Greenland Greenland ice core Greenland Ice core Project GRIP ice core Ice Sheet The Cryosphere |
op_source |
EPIC3The Cryosphere, Copernicus Publications on behalf of the European Geosciences Union, 15(8), pp. 3655-3679 |
op_relation |
https://epic.awi.de/id/eprint/54441/1/tc-15-3655-2021.pdf https://hdl.handle.net/ Gerber, T. , Schøtt Hvidberg, C. , Olander Rasmussen, S. , Franke, S. orcid:0000-0001-8462-4379 , Sinnl, G. , Grinsted, A. , Jansen, D. orcid:0000-0002-4412-5820 and Dahl-Jensen, D. (2021) Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model , The Cryosphere, 15 (8), pp. 3655-3679 . doi:10.5194/tc-15-3655-2021 <https://doi.org/10.5194/tc-15-3655-2021> , hdl:10013/epic.e961618f-2afa-4479-87cc-195eebd34c3b |
op_doi |
https://doi.org/10.5194/tc-15-3655-2021 |
container_title |
The Cryosphere |
container_volume |
15 |
container_issue |
8 |
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3655 |
op_container_end_page |
3679 |
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1766399602132516864 |