Oxygen stable isotopes during the Last Glacial Maximum climate: perspectives from data–model (<i>i</i>LOVECLIM) comparison
We use the fully coupled atmosphere–ocean three-dimensional model of intermediate complexity <i>i</i>LOVECLIM to simulate the climate and oxygen stable isotopic signal during the Last Glacial Maximum (LGM, 21 000 years). By using a model that is able to explicitly simulate the sensor (δ&...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-11-01
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| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/10/1939/2014/cp-10-1939-2014.pdf |
| _version_ | 1828801898778460160 |
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| author | T. Caley D. M. Roche C. Waelbroeck E. Michel |
| author_facet | T. Caley D. M. Roche C. Waelbroeck E. Michel |
| author_sort | T. Caley |
| collection | DOAJ |
| description | We use the fully coupled atmosphere–ocean three-dimensional model of
intermediate complexity <i>i</i>LOVECLIM to simulate the
climate and oxygen stable isotopic signal during the Last Glacial Maximum
(LGM, 21 000 years). By using a model that is able to explicitly simulate
the sensor (δ<sup>18</sup>O), results can be directly
compared with data from climatic archives in the different realms.
<br><br>
Our results indicate that <i>i</i>LOVECLIM
reproduces well the main feature of the LGM climate in the atmospheric and
oceanic components. The annual mean δ<sup>18</sup>O in
precipitation shows more depleted values in the northern and southern high
latitudes during the LGM. The model reproduces very well the spatial
gradient observed in ice core records over the Greenland ice sheet. We
observe a general pattern toward more enriched values for continental
calcite δ<sup>18</sup>O in the model at the LGM, in
agreement with speleothem data. This can be explained by both a general
atmospheric cooling in the tropical and subtropical regions and a reduction
in precipitation as confirmed by reconstruction derived from pollens and
plant macrofossils.
<br><br>
Data–model comparison for sea surface temperature indicates that
<i>i</i>LOVECLIM is capable to satisfyingly simulate the
change in oceanic surface conditions between the LGM and present. Our
data–model comparison for calcite δ<sup>18</sup>O allows
investigating the large discrepancies with respect to glacial temperatures
recorded by different microfossil proxies in the North Atlantic region. The
results argue for a strong mean annual cooling in the area south of
Iceland and Greenland between the LGM and present (> 6 °C),
supporting the foraminifera transfer function reconstruction but in
disagreement with alkenones and dinocyst reconstructions. The data–model
comparison also reveals that large positive calcite δ<sup>18</sup>O anomaly in the Southern Ocean may be explained by
an important cooling, although the driver of this pattern is unclear. We
deduce a large positive δ<sup>18</sup>Osw anomaly for
the north Indian Ocean that contrasts with a large negative δ<sup>18</sup>Osw anomaly in the China Sea between the LGM and the
present. This pattern may be linked to changes in the hydrological cycle
over these regions.
<br><br>
Our simulation of the deep ocean suggests that changes in δ<sup>18</sup>Osw between the LGM and the present are not spatially
homogeneous. This is supported by reconstructions derived from pore fluids in
deep-sea sediments. The model underestimates the deep ocean cooling thus
biasing the comparison with benthic calcite δ<sup>18</sup>O data. Nonetheless, our data–model comparison
supports a heterogeneous cooling of a few degrees (2–4 °C) in the LGM
Ocean. |
| first_indexed | 2024-12-12T06:54:25Z |
| format | Article |
| id | doaj.art-3f9b546906274011a3303bf4789775db |
| institution | Directory Open Access Journal |
| issn | 1814-9324 1814-9332 |
| language | English |
| last_indexed | 2024-12-12T06:54:25Z |
| publishDate | 2014-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj.art-3f9b546906274011a3303bf4789775db2022-12-22T00:33:59ZengCopernicus PublicationsClimate of the Past1814-93241814-93322014-11-011061939195510.5194/cp-10-1939-2014Oxygen stable isotopes during the Last Glacial Maximum climate: perspectives from data–model (<i>i</i>LOVECLIM) comparisonT. Caley0D. M. Roche1C. Waelbroeck2E. Michel3Earth and Climate Cluster, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The NetherlandsEarth and Climate Cluster, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The NetherlandsLaboratoire des Sciences du Climat et de l'Environnement (LSCE), CEA/CNRS-INSU/UVSQ, Gif-sur-Yvette Cedex, FranceLaboratoire des Sciences du Climat et de l'Environnement (LSCE), CEA/CNRS-INSU/UVSQ, Gif-sur-Yvette Cedex, FranceWe use the fully coupled atmosphere–ocean three-dimensional model of intermediate complexity <i>i</i>LOVECLIM to simulate the climate and oxygen stable isotopic signal during the Last Glacial Maximum (LGM, 21 000 years). By using a model that is able to explicitly simulate the sensor (δ<sup>18</sup>O), results can be directly compared with data from climatic archives in the different realms. <br><br> Our results indicate that <i>i</i>LOVECLIM reproduces well the main feature of the LGM climate in the atmospheric and oceanic components. The annual mean δ<sup>18</sup>O in precipitation shows more depleted values in the northern and southern high latitudes during the LGM. The model reproduces very well the spatial gradient observed in ice core records over the Greenland ice sheet. We observe a general pattern toward more enriched values for continental calcite δ<sup>18</sup>O in the model at the LGM, in agreement with speleothem data. This can be explained by both a general atmospheric cooling in the tropical and subtropical regions and a reduction in precipitation as confirmed by reconstruction derived from pollens and plant macrofossils. <br><br> Data–model comparison for sea surface temperature indicates that <i>i</i>LOVECLIM is capable to satisfyingly simulate the change in oceanic surface conditions between the LGM and present. Our data–model comparison for calcite δ<sup>18</sup>O allows investigating the large discrepancies with respect to glacial temperatures recorded by different microfossil proxies in the North Atlantic region. The results argue for a strong mean annual cooling in the area south of Iceland and Greenland between the LGM and present (> 6 °C), supporting the foraminifera transfer function reconstruction but in disagreement with alkenones and dinocyst reconstructions. The data–model comparison also reveals that large positive calcite δ<sup>18</sup>O anomaly in the Southern Ocean may be explained by an important cooling, although the driver of this pattern is unclear. We deduce a large positive δ<sup>18</sup>Osw anomaly for the north Indian Ocean that contrasts with a large negative δ<sup>18</sup>Osw anomaly in the China Sea between the LGM and the present. This pattern may be linked to changes in the hydrological cycle over these regions. <br><br> Our simulation of the deep ocean suggests that changes in δ<sup>18</sup>Osw between the LGM and the present are not spatially homogeneous. This is supported by reconstructions derived from pore fluids in deep-sea sediments. The model underestimates the deep ocean cooling thus biasing the comparison with benthic calcite δ<sup>18</sup>O data. Nonetheless, our data–model comparison supports a heterogeneous cooling of a few degrees (2–4 °C) in the LGM Ocean.http://www.clim-past.net/10/1939/2014/cp-10-1939-2014.pdf |
| spellingShingle | T. Caley D. M. Roche C. Waelbroeck E. Michel Oxygen stable isotopes during the Last Glacial Maximum climate: perspectives from data–model (<i>i</i>LOVECLIM) comparison Climate of the Past |
| title | Oxygen stable isotopes during the Last Glacial Maximum climate: perspectives from data–model (<i>i</i>LOVECLIM) comparison |
| title_full | Oxygen stable isotopes during the Last Glacial Maximum climate: perspectives from data–model (<i>i</i>LOVECLIM) comparison |
| title_fullStr | Oxygen stable isotopes during the Last Glacial Maximum climate: perspectives from data–model (<i>i</i>LOVECLIM) comparison |
| title_full_unstemmed | Oxygen stable isotopes during the Last Glacial Maximum climate: perspectives from data–model (<i>i</i>LOVECLIM) comparison |
| title_short | Oxygen stable isotopes during the Last Glacial Maximum climate: perspectives from data–model (<i>i</i>LOVECLIM) comparison |
| title_sort | oxygen stable isotopes during the last glacial maximum climate perspectives from data model i i i loveclim comparison |
| url | http://www.clim-past.net/10/1939/2014/cp-10-1939-2014.pdf |
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