Atlantic water inflow to Labrador Sea and its interaction with ice sheet dynamics during the Holocene
The hydrodynamics of the Labrador Sea, controlled by the complex interplay of oceanographic, atmospheric and ice-sheet processes, play a crucial role for the Atlantic Meridional Overturning Circulation (AMOC). An improved understanding of the hydrodynamics and its forcing in the past could therefore...
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ftucambridgeesc:oai:eprints.esc.cam.ac.uk:6013 2023-05-15T15:35:08+02:00 Atlantic water inflow to Labrador Sea and its interaction with ice sheet dynamics during the Holocene Weiser, Jens Titschack, Jürgen Kienast, Markus McCave, Ian Nicholas Lochte, Annalena Antonia Saini, Jeetendra Stein, Rüdiger Hebbeln, Dierk 2021 text http://eprints.esc.cam.ac.uk/6013/ http://eprints.esc.cam.ac.uk/6013/1/1-s2.0-S0277379121000408-main.pdf https://doi.org/10.1016/j.quascirev.2021.106833 en eng Elsevier http://eprints.esc.cam.ac.uk/6013/1/1-s2.0-S0277379121000408-main.pdf Weiser, Jens and Titschack, Jürgen and Kienast, Markus and McCave, Ian Nicholas and Lochte, Annalena Antonia and Saini, Jeetendra and Stein, Rüdiger and Hebbeln, Dierk (2021) Atlantic water inflow to Labrador Sea and its interaction with ice sheet dynamics during the Holocene. Quaternary Science Reviews, 256. p. 106833. ISSN 0277-3791 DOI https://doi.org/10.1016/j.quascirev.2021.106833 <https://doi.org/10.1016/j.quascirev.2021.106833> cc_by CC-BY 01 - Climate Change and Earth-Ocean Atmosphere Systems Article PeerReviewed 2021 ftucambridgeesc https://doi.org/10.1016/j.quascirev.2021.106833 2021-03-04T23:16:37Z The hydrodynamics of the Labrador Sea, controlled by the complex interplay of oceanographic, atmospheric and ice-sheet processes, play a crucial role for the Atlantic Meridional Overturning Circulation (AMOC). An improved understanding of the hydrodynamics and its forcing in the past could therefore hold a key to understanding its future behaviour. At present, there is a remarkable temporal mismatch, in that the largely microfossil-based reconstructions of Holocene Atlantic-water inflow/influence in the Labrador Sea and Baffin Bay appear to lag grain size-based current strength reconstructions from the adjacent North Atlantic by > 2ka. Here, we present the first current strength record from the West Greenland shelf off Nuuk to reconstruct Atlantic Water (AW)-inflow to the Labrador Sea via the West Greenland Current. Our data show that the Holocene AW-inflow into Labrador Sea is well aligned with the Holocene Speed Maximum documented in the North Atlantic (McCave and Andrews, 2019; Quat. Sci. Rev. 223), suggesting a close coupling with the AMOC. The observed lag between the microfossil-based records and the Holocene Speed Maximum can be explained when considering the presence of an extended meltwater lens that prevented the shoaling of the inflowing Atlantic waters. Once the meltwater discharge waned after the cessation of large-scale melting of the surrounding ice sheets, the AW could influence the surface waters, independently of the strength of its inflow. Only then was an effective ocean-atmosphere heat transfer enabled, triggering the comparably late onset of the regional Holocene Thermal Maximum. Furthermore, sediment geochemical analyses show that short term cooling events, such as the 8.2 ka event related to the final drainage of glacial Lake Agassiz, lead to glacier advances of the Greenland Ice Sheet. Since the grain size data show that these events had no influence on the AW-inflow to the north eastern Labrador Sea, these advances must have been caused by atmospheric cooling. Consequently, we argue that (i) in this region, surface water-based proxies register AW influence rather than inflow (ii) the AW inflow into the Labrador Sea is controlled by the AMOC, but (iii) its impact on an effective ocean-atmosphere heat transfer was hindered by a prevailing meltwater lens in the early Holocene, i.e. until the cessation of large-scale melting of the surrounding ice sheets. Article in Journal/Newspaper Baffin Bay Baffin Bay Baffin glacier Greenland Ice Sheet Labrador Sea North Atlantic Nuuk University of Cambridge, Department of Earth Sciences: ESC Publications Baffin Bay Glacial Lake ENVELOPE(-129.463,-129.463,58.259,58.259) Greenland Nuuk ENVELOPE(-52.150,-52.150,68.717,68.717) Quaternary Science Reviews 256 106833 |
institution |
Open Polar |
collection |
University of Cambridge, Department of Earth Sciences: ESC Publications |
op_collection_id |
ftucambridgeesc |
language |
English |
topic |
01 - Climate Change and Earth-Ocean Atmosphere Systems |
spellingShingle |
01 - Climate Change and Earth-Ocean Atmosphere Systems Weiser, Jens Titschack, Jürgen Kienast, Markus McCave, Ian Nicholas Lochte, Annalena Antonia Saini, Jeetendra Stein, Rüdiger Hebbeln, Dierk Atlantic water inflow to Labrador Sea and its interaction with ice sheet dynamics during the Holocene |
topic_facet |
01 - Climate Change and Earth-Ocean Atmosphere Systems |
description |
The hydrodynamics of the Labrador Sea, controlled by the complex interplay of oceanographic, atmospheric and ice-sheet processes, play a crucial role for the Atlantic Meridional Overturning Circulation (AMOC). An improved understanding of the hydrodynamics and its forcing in the past could therefore hold a key to understanding its future behaviour. At present, there is a remarkable temporal mismatch, in that the largely microfossil-based reconstructions of Holocene Atlantic-water inflow/influence in the Labrador Sea and Baffin Bay appear to lag grain size-based current strength reconstructions from the adjacent North Atlantic by > 2ka. Here, we present the first current strength record from the West Greenland shelf off Nuuk to reconstruct Atlantic Water (AW)-inflow to the Labrador Sea via the West Greenland Current. Our data show that the Holocene AW-inflow into Labrador Sea is well aligned with the Holocene Speed Maximum documented in the North Atlantic (McCave and Andrews, 2019; Quat. Sci. Rev. 223), suggesting a close coupling with the AMOC. The observed lag between the microfossil-based records and the Holocene Speed Maximum can be explained when considering the presence of an extended meltwater lens that prevented the shoaling of the inflowing Atlantic waters. Once the meltwater discharge waned after the cessation of large-scale melting of the surrounding ice sheets, the AW could influence the surface waters, independently of the strength of its inflow. Only then was an effective ocean-atmosphere heat transfer enabled, triggering the comparably late onset of the regional Holocene Thermal Maximum. Furthermore, sediment geochemical analyses show that short term cooling events, such as the 8.2 ka event related to the final drainage of glacial Lake Agassiz, lead to glacier advances of the Greenland Ice Sheet. Since the grain size data show that these events had no influence on the AW-inflow to the north eastern Labrador Sea, these advances must have been caused by atmospheric cooling. Consequently, we argue that (i) in this region, surface water-based proxies register AW influence rather than inflow (ii) the AW inflow into the Labrador Sea is controlled by the AMOC, but (iii) its impact on an effective ocean-atmosphere heat transfer was hindered by a prevailing meltwater lens in the early Holocene, i.e. until the cessation of large-scale melting of the surrounding ice sheets. |
format |
Article in Journal/Newspaper |
author |
Weiser, Jens Titschack, Jürgen Kienast, Markus McCave, Ian Nicholas Lochte, Annalena Antonia Saini, Jeetendra Stein, Rüdiger Hebbeln, Dierk |
author_facet |
Weiser, Jens Titschack, Jürgen Kienast, Markus McCave, Ian Nicholas Lochte, Annalena Antonia Saini, Jeetendra Stein, Rüdiger Hebbeln, Dierk |
author_sort |
Weiser, Jens |
title |
Atlantic water inflow to Labrador Sea and its interaction with ice sheet dynamics during the Holocene |
title_short |
Atlantic water inflow to Labrador Sea and its interaction with ice sheet dynamics during the Holocene |
title_full |
Atlantic water inflow to Labrador Sea and its interaction with ice sheet dynamics during the Holocene |
title_fullStr |
Atlantic water inflow to Labrador Sea and its interaction with ice sheet dynamics during the Holocene |
title_full_unstemmed |
Atlantic water inflow to Labrador Sea and its interaction with ice sheet dynamics during the Holocene |
title_sort |
atlantic water inflow to labrador sea and its interaction with ice sheet dynamics during the holocene |
publisher |
Elsevier |
publishDate |
2021 |
url |
http://eprints.esc.cam.ac.uk/6013/ http://eprints.esc.cam.ac.uk/6013/1/1-s2.0-S0277379121000408-main.pdf https://doi.org/10.1016/j.quascirev.2021.106833 |
long_lat |
ENVELOPE(-129.463,-129.463,58.259,58.259) ENVELOPE(-52.150,-52.150,68.717,68.717) |
geographic |
Baffin Bay Glacial Lake Greenland Nuuk |
geographic_facet |
Baffin Bay Glacial Lake Greenland Nuuk |
genre |
Baffin Bay Baffin Bay Baffin glacier Greenland Ice Sheet Labrador Sea North Atlantic Nuuk |
genre_facet |
Baffin Bay Baffin Bay Baffin glacier Greenland Ice Sheet Labrador Sea North Atlantic Nuuk |
op_relation |
http://eprints.esc.cam.ac.uk/6013/1/1-s2.0-S0277379121000408-main.pdf Weiser, Jens and Titschack, Jürgen and Kienast, Markus and McCave, Ian Nicholas and Lochte, Annalena Antonia and Saini, Jeetendra and Stein, Rüdiger and Hebbeln, Dierk (2021) Atlantic water inflow to Labrador Sea and its interaction with ice sheet dynamics during the Holocene. Quaternary Science Reviews, 256. p. 106833. ISSN 0277-3791 DOI https://doi.org/10.1016/j.quascirev.2021.106833 <https://doi.org/10.1016/j.quascirev.2021.106833> |
op_rights |
cc_by |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1016/j.quascirev.2021.106833 |
container_title |
Quaternary Science Reviews |
container_volume |
256 |
container_start_page |
106833 |
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1766365428548894720 |