Age models and summer sea surface temperature and winter sea ice concentration for the EPILOG-LGM time slice in the Pacific Southern Ocean, supplement to: Benz, Verena; Esper, Oliver; Gersonde, Rainer; Lamy, Frank; Tiedemann, Ralf (2016): Last Glacial Maximum sea surface temperature and sea-ice extent in the Pacific sector of the Southern Ocean. Quaternary Science Reviews, 146, 216-237
Sea surface temperatures and sea-ice extent are the most critical variables to evaluate the Southern Ocean paleoceanographic evolution in relation to the development of the global carbon cycle, atmospheric CO2 variability and ocean-atmosphere circulation. In contrast to the Atlantic and the Indian s...
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Format: | Article in Journal/Newspaper |
Language: | English |
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PANGAEA - Data Publisher for Earth & Environmental Science
2016
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Online Access: | https://dx.doi.org/10.1594/pangaea.849115 https://doi.pangaea.de/10.1594/PANGAEA.849115 |
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Open Polar |
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DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
English |
topic |
Paleoenvironmental Reconstructions from Marine Sediments @ AWI AWI_Paleo |
spellingShingle |
Paleoenvironmental Reconstructions from Marine Sediments @ AWI AWI_Paleo Benz, Verena Esper, Oliver Gersonde, Rainer Lamy, Frank Tiedemann, Ralf Age models and summer sea surface temperature and winter sea ice concentration for the EPILOG-LGM time slice in the Pacific Southern Ocean, supplement to: Benz, Verena; Esper, Oliver; Gersonde, Rainer; Lamy, Frank; Tiedemann, Ralf (2016): Last Glacial Maximum sea surface temperature and sea-ice extent in the Pacific sector of the Southern Ocean. Quaternary Science Reviews, 146, 216-237 |
topic_facet |
Paleoenvironmental Reconstructions from Marine Sediments @ AWI AWI_Paleo |
description |
Sea surface temperatures and sea-ice extent are the most critical variables to evaluate the Southern Ocean paleoceanographic evolution in relation to the development of the global carbon cycle, atmospheric CO2 variability and ocean-atmosphere circulation. In contrast to the Atlantic and the Indian sectors, the Pacific sector of the Southern Ocean has been insufficiently investigated so far. To cover this gap of information we present diatom-based estimates of summer sea surface temperature (SSST) and winter sea-ice concentration (WSI) from 17 sites in the polar South Pacific to study the Last Glacial Maximum (LGM) at the EPILOG time slice (19,000-23,000 cal. years BP). Applied statistical methods are the Imbrie and Kipp Method (IKM) and the Modern Analog Technique (MAT) to estimate temperature and sea-ice concentration, respectively. Our data display a distinct LGM east-west differentiation in SSST and WSI with steeper latitudinal temperature gradients and a winter sea-ice edge located consistently north of the Pacific-Antarctic Ridge in the Ross sea sector. In the eastern sector of our study area, which is governed by the Amundsen Abyssal Plain, the estimates yield weaker latitudinal SSST gradients together with a variable extended winter sea-ice field. In this sector, sea-ice extent may have reached sporadically the area of the present Subantarctic Front at its maximum LGM expansion. This pattern points to topographic forcing as major controller of the frontal system location and sea-ice extent in the western Pacific sector whereas atmospheric conditions like the Southern Annular Mode and the ENSO affected the oceanographic conditions in the eastern Pacific sector. Although it is difficult to depict the location and the physical nature of frontal systems separating the glacial Southern Ocean water masses into different zones, we found a distinct temperature gradient in latitudes straddled by the modern Southern Subtropical Front. Considering that the glacial temperatures north of this zone are similar to the modern, we suggest that this represents the Glacial Southern Subtropical Front (GSSTF), which delimits the zone of strongest glacial SSST cooling (>4K) to its North. The southern boundary of the zone of maximum cooling is close to the glacial 4°C isotherm. This isotherm, which is in the range of SSST at the modern Antarctic Polar Front (APF), represents a circum-Antarctic feature and marks the northern edge of the glacial Antarctic Circumpolar Current (ACC). We also assume that a glacial front was established at the northern average winter sea ice edge, comparable with the modern Southern Antarctic Circumpolar Current Front (SACCF). During the glacial, this front would be located in the area of the modern APF. The northward deflection of colder than modern surface waters along the South American continent leads to a significant cooling of the glacial Humboldt Current surface waters (4-8K), which affects the temperature regimes as far north as into tropical latitudes. The glacial reduction of ACC temperatures may also result in the significant cooling in the Atlantic and Indian Southern Ocean, thus may enhance thermal differentiation of the Southern Ocean and Antarctic continental cooling. Comparison with temperature and sea ice simulations for the last glacial based on numerical simulations show that the majority of modern models overestimate summer and winter sea ice cover and that there exists few models that reproduce our temperature data rather well. |
format |
Article in Journal/Newspaper |
author |
Benz, Verena Esper, Oliver Gersonde, Rainer Lamy, Frank Tiedemann, Ralf |
author_facet |
Benz, Verena Esper, Oliver Gersonde, Rainer Lamy, Frank Tiedemann, Ralf |
author_sort |
Benz, Verena |
title |
Age models and summer sea surface temperature and winter sea ice concentration for the EPILOG-LGM time slice in the Pacific Southern Ocean, supplement to: Benz, Verena; Esper, Oliver; Gersonde, Rainer; Lamy, Frank; Tiedemann, Ralf (2016): Last Glacial Maximum sea surface temperature and sea-ice extent in the Pacific sector of the Southern Ocean. Quaternary Science Reviews, 146, 216-237 |
title_short |
Age models and summer sea surface temperature and winter sea ice concentration for the EPILOG-LGM time slice in the Pacific Southern Ocean, supplement to: Benz, Verena; Esper, Oliver; Gersonde, Rainer; Lamy, Frank; Tiedemann, Ralf (2016): Last Glacial Maximum sea surface temperature and sea-ice extent in the Pacific sector of the Southern Ocean. Quaternary Science Reviews, 146, 216-237 |
title_full |
Age models and summer sea surface temperature and winter sea ice concentration for the EPILOG-LGM time slice in the Pacific Southern Ocean, supplement to: Benz, Verena; Esper, Oliver; Gersonde, Rainer; Lamy, Frank; Tiedemann, Ralf (2016): Last Glacial Maximum sea surface temperature and sea-ice extent in the Pacific sector of the Southern Ocean. Quaternary Science Reviews, 146, 216-237 |
title_fullStr |
Age models and summer sea surface temperature and winter sea ice concentration for the EPILOG-LGM time slice in the Pacific Southern Ocean, supplement to: Benz, Verena; Esper, Oliver; Gersonde, Rainer; Lamy, Frank; Tiedemann, Ralf (2016): Last Glacial Maximum sea surface temperature and sea-ice extent in the Pacific sector of the Southern Ocean. Quaternary Science Reviews, 146, 216-237 |
title_full_unstemmed |
Age models and summer sea surface temperature and winter sea ice concentration for the EPILOG-LGM time slice in the Pacific Southern Ocean, supplement to: Benz, Verena; Esper, Oliver; Gersonde, Rainer; Lamy, Frank; Tiedemann, Ralf (2016): Last Glacial Maximum sea surface temperature and sea-ice extent in the Pacific sector of the Southern Ocean. Quaternary Science Reviews, 146, 216-237 |
title_sort |
age models and summer sea surface temperature and winter sea ice concentration for the epilog-lgm time slice in the pacific southern ocean, supplement to: benz, verena; esper, oliver; gersonde, rainer; lamy, frank; tiedemann, ralf (2016): last glacial maximum sea surface temperature and sea-ice extent in the pacific sector of the southern ocean. quaternary science reviews, 146, 216-237 |
publisher |
PANGAEA - Data Publisher for Earth & Environmental Science |
publishDate |
2016 |
url |
https://dx.doi.org/10.1594/pangaea.849115 https://doi.pangaea.de/10.1594/PANGAEA.849115 |
long_lat |
ENVELOPE(-125.000,-125.000,-63.500,-63.500) |
geographic |
Antarctic Southern Ocean Ross Sea Pacific Indian Amundsen Abyssal Plain |
geographic_facet |
Antarctic Southern Ocean Ross Sea Pacific Indian Amundsen Abyssal Plain |
genre |
Antarc* Antarctic Ross Sea Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Ross Sea Sea ice Southern Ocean |
op_relation |
https://dx.doi.org/10.1016/j.quascirev.2016.06.006 |
op_rights |
Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode cc-by-3.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/pangaea.849115 https://doi.org/10.1016/j.quascirev.2016.06.006 |
_version_ |
1766066747431976960 |
spelling |
ftdatacite:10.1594/pangaea.849115 2023-05-15T13:35:31+02:00 Age models and summer sea surface temperature and winter sea ice concentration for the EPILOG-LGM time slice in the Pacific Southern Ocean, supplement to: Benz, Verena; Esper, Oliver; Gersonde, Rainer; Lamy, Frank; Tiedemann, Ralf (2016): Last Glacial Maximum sea surface temperature and sea-ice extent in the Pacific sector of the Southern Ocean. Quaternary Science Reviews, 146, 216-237 Benz, Verena Esper, Oliver Gersonde, Rainer Lamy, Frank Tiedemann, Ralf 2016 application/zip https://dx.doi.org/10.1594/pangaea.849115 https://doi.pangaea.de/10.1594/PANGAEA.849115 en eng PANGAEA - Data Publisher for Earth & Environmental Science https://dx.doi.org/10.1016/j.quascirev.2016.06.006 Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode cc-by-3.0 CC-BY Paleoenvironmental Reconstructions from Marine Sediments @ AWI AWI_Paleo Collection article Supplementary Collection of Datasets 2016 ftdatacite https://doi.org/10.1594/pangaea.849115 https://doi.org/10.1016/j.quascirev.2016.06.006 2021-11-05T12:55:41Z Sea surface temperatures and sea-ice extent are the most critical variables to evaluate the Southern Ocean paleoceanographic evolution in relation to the development of the global carbon cycle, atmospheric CO2 variability and ocean-atmosphere circulation. In contrast to the Atlantic and the Indian sectors, the Pacific sector of the Southern Ocean has been insufficiently investigated so far. To cover this gap of information we present diatom-based estimates of summer sea surface temperature (SSST) and winter sea-ice concentration (WSI) from 17 sites in the polar South Pacific to study the Last Glacial Maximum (LGM) at the EPILOG time slice (19,000-23,000 cal. years BP). Applied statistical methods are the Imbrie and Kipp Method (IKM) and the Modern Analog Technique (MAT) to estimate temperature and sea-ice concentration, respectively. Our data display a distinct LGM east-west differentiation in SSST and WSI with steeper latitudinal temperature gradients and a winter sea-ice edge located consistently north of the Pacific-Antarctic Ridge in the Ross sea sector. In the eastern sector of our study area, which is governed by the Amundsen Abyssal Plain, the estimates yield weaker latitudinal SSST gradients together with a variable extended winter sea-ice field. In this sector, sea-ice extent may have reached sporadically the area of the present Subantarctic Front at its maximum LGM expansion. This pattern points to topographic forcing as major controller of the frontal system location and sea-ice extent in the western Pacific sector whereas atmospheric conditions like the Southern Annular Mode and the ENSO affected the oceanographic conditions in the eastern Pacific sector. Although it is difficult to depict the location and the physical nature of frontal systems separating the glacial Southern Ocean water masses into different zones, we found a distinct temperature gradient in latitudes straddled by the modern Southern Subtropical Front. Considering that the glacial temperatures north of this zone are similar to the modern, we suggest that this represents the Glacial Southern Subtropical Front (GSSTF), which delimits the zone of strongest glacial SSST cooling (>4K) to its North. The southern boundary of the zone of maximum cooling is close to the glacial 4°C isotherm. This isotherm, which is in the range of SSST at the modern Antarctic Polar Front (APF), represents a circum-Antarctic feature and marks the northern edge of the glacial Antarctic Circumpolar Current (ACC). We also assume that a glacial front was established at the northern average winter sea ice edge, comparable with the modern Southern Antarctic Circumpolar Current Front (SACCF). During the glacial, this front would be located in the area of the modern APF. The northward deflection of colder than modern surface waters along the South American continent leads to a significant cooling of the glacial Humboldt Current surface waters (4-8K), which affects the temperature regimes as far north as into tropical latitudes. The glacial reduction of ACC temperatures may also result in the significant cooling in the Atlantic and Indian Southern Ocean, thus may enhance thermal differentiation of the Southern Ocean and Antarctic continental cooling. Comparison with temperature and sea ice simulations for the last glacial based on numerical simulations show that the majority of modern models overestimate summer and winter sea ice cover and that there exists few models that reproduce our temperature data rather well. Article in Journal/Newspaper Antarc* Antarctic Ross Sea Sea ice Southern Ocean DataCite Metadata Store (German National Library of Science and Technology) Antarctic Southern Ocean Ross Sea Pacific Indian Amundsen Abyssal Plain ENVELOPE(-125.000,-125.000,-63.500,-63.500) |