Heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes
Heinrich events, identified as enhanced ice-rafted detritus (IRD) in North Atlantic deep sea sediments (Heinrich, 1988; Hemming, 2004) have classically been attributed to Laurentide ice-sheet (LIS) instabilities (MacAyeal, 1993; Calov et al., 2002; Hulbe et al., 2004) and assumed to lead to importan...
Published in: | Climate of the Past |
---|---|
Main Authors: | , , , , , , , , |
Format: | Text |
Language: | English |
Published: |
2018
|
Subjects: | |
Online Access: | https://doi.org/10.5194/cp-7-1297-2011 https://cp.copernicus.org/articles/7/1297/2011/ |
id |
ftcopernicus:oai:publications.copernicus.org:cp11407 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:cp11407 2023-05-15T16:35:39+02:00 Heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes Álvarez-Solas, J. Montoya, M. Ritz, C. Ramstein, G. Charbit, S. Dumas, C. Nisancioglu, K. Dokken, T. Ganopolski, A. 2018-09-27 application/pdf https://doi.org/10.5194/cp-7-1297-2011 https://cp.copernicus.org/articles/7/1297/2011/ eng eng doi:10.5194/cp-7-1297-2011 https://cp.copernicus.org/articles/7/1297/2011/ eISSN: 1814-9332 Text 2018 ftcopernicus https://doi.org/10.5194/cp-7-1297-2011 2020-07-20T16:25:58Z Heinrich events, identified as enhanced ice-rafted detritus (IRD) in North Atlantic deep sea sediments (Heinrich, 1988; Hemming, 2004) have classically been attributed to Laurentide ice-sheet (LIS) instabilities (MacAyeal, 1993; Calov et al., 2002; Hulbe et al., 2004) and assumed to lead to important disruptions of the Atlantic meridional overturning circulation (AMOC) and North Atlantic deep water (NADW) formation. However, recent paleoclimate data have revealed that most of these events probably occurred after the AMOC had already slowed down or/and NADW largely collapsed, within about a thousand years (Hall et al., 2006; Hemming, 2004; Jonkers et al., 2010; Roche et al., 2004), implying that the initial AMOC reduction could not have been caused by the Heinrich events themselves. Here we propose an alternative driving mechanism, specifically for Heinrich event 1 (H1; 18 to 15 ka BP), by which North Atlantic ocean circulation changes are found to have strong impacts on LIS dynamics. By combining simulations with a coupled climate model and a three-dimensional ice sheet model, our study illustrates how reduced NADW and AMOC weakening lead to a subsurface warming in the Nordic and Labrador Seas resulting in rapid melting of the Hudson Strait and Labrador ice shelves. Lack of buttressing by the ice shelves implies a substantial ice-stream acceleration, enhanced ice-discharge and sea level rise, with peak values 500–1500 yr after the initial AMOC reduction. Our scenario modifies the previous paradigm of H1 by solving the paradox of its occurrence during a cold surface period, and highlights the importance of taking into account the effects of oceanic circulation on ice-sheets dynamics in order to elucidate the triggering mechanism of Heinrich events. Text Hudson Strait Ice Sheet Ice Shelves NADW North Atlantic Deep Water North Atlantic Copernicus Publications: E-Journals Hudson Hudson Strait ENVELOPE(-70.000,-70.000,62.000,62.000) Climate of the Past 7 4 1297 1306 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Heinrich events, identified as enhanced ice-rafted detritus (IRD) in North Atlantic deep sea sediments (Heinrich, 1988; Hemming, 2004) have classically been attributed to Laurentide ice-sheet (LIS) instabilities (MacAyeal, 1993; Calov et al., 2002; Hulbe et al., 2004) and assumed to lead to important disruptions of the Atlantic meridional overturning circulation (AMOC) and North Atlantic deep water (NADW) formation. However, recent paleoclimate data have revealed that most of these events probably occurred after the AMOC had already slowed down or/and NADW largely collapsed, within about a thousand years (Hall et al., 2006; Hemming, 2004; Jonkers et al., 2010; Roche et al., 2004), implying that the initial AMOC reduction could not have been caused by the Heinrich events themselves. Here we propose an alternative driving mechanism, specifically for Heinrich event 1 (H1; 18 to 15 ka BP), by which North Atlantic ocean circulation changes are found to have strong impacts on LIS dynamics. By combining simulations with a coupled climate model and a three-dimensional ice sheet model, our study illustrates how reduced NADW and AMOC weakening lead to a subsurface warming in the Nordic and Labrador Seas resulting in rapid melting of the Hudson Strait and Labrador ice shelves. Lack of buttressing by the ice shelves implies a substantial ice-stream acceleration, enhanced ice-discharge and sea level rise, with peak values 500–1500 yr after the initial AMOC reduction. Our scenario modifies the previous paradigm of H1 by solving the paradox of its occurrence during a cold surface period, and highlights the importance of taking into account the effects of oceanic circulation on ice-sheets dynamics in order to elucidate the triggering mechanism of Heinrich events. |
format |
Text |
author |
Álvarez-Solas, J. Montoya, M. Ritz, C. Ramstein, G. Charbit, S. Dumas, C. Nisancioglu, K. Dokken, T. Ganopolski, A. |
spellingShingle |
Álvarez-Solas, J. Montoya, M. Ritz, C. Ramstein, G. Charbit, S. Dumas, C. Nisancioglu, K. Dokken, T. Ganopolski, A. Heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes |
author_facet |
Álvarez-Solas, J. Montoya, M. Ritz, C. Ramstein, G. Charbit, S. Dumas, C. Nisancioglu, K. Dokken, T. Ganopolski, A. |
author_sort |
Álvarez-Solas, J. |
title |
Heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes |
title_short |
Heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes |
title_full |
Heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes |
title_fullStr |
Heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes |
title_full_unstemmed |
Heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes |
title_sort |
heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes |
publishDate |
2018 |
url |
https://doi.org/10.5194/cp-7-1297-2011 https://cp.copernicus.org/articles/7/1297/2011/ |
long_lat |
ENVELOPE(-70.000,-70.000,62.000,62.000) |
geographic |
Hudson Hudson Strait |
geographic_facet |
Hudson Hudson Strait |
genre |
Hudson Strait Ice Sheet Ice Shelves NADW North Atlantic Deep Water North Atlantic |
genre_facet |
Hudson Strait Ice Sheet Ice Shelves NADW North Atlantic Deep Water North Atlantic |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-7-1297-2011 https://cp.copernicus.org/articles/7/1297/2011/ |
op_doi |
https://doi.org/10.5194/cp-7-1297-2011 |
container_title |
Climate of the Past |
container_volume |
7 |
container_issue |
4 |
container_start_page |
1297 |
op_container_end_page |
1306 |
_version_ |
1766025922015657984 |