Sensitivity of interglacial Greenland temperature and δ18O: ice core data, orbital and increased CO2 climate simulations
The sensitivity of interglacial Greenland temperature to orbital and CO 2 forcing is investigated using the NorthGRIP ice core data and coupled ocean-atmosphere IPSL-CM4 model simulations. These simulations were conducted in response to different interglacial orbital configurations, and to increased...
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Language: | English |
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Online Access: | https://doi.org/10.5194/cp-7-1041-2011 https://cp.copernicus.org/articles/7/1041/2011/ |
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ftcopernicus:oai:publications.copernicus.org:cp11559 2023-05-15T15:04:51+02:00 Sensitivity of interglacial Greenland temperature and δ18O: ice core data, orbital and increased CO2 climate simulations Masson-Delmotte, V. Braconnot, P. Hoffmann, G. Jouzel, J. Kageyama, M. Landais, A. Lejeune, Q. Risi, C. Sime, L. Sjolte, J. Swingedouw, D. Vinther, B. 2018-09-27 info:eu-repo/semantics/application/pdf https://doi.org/10.5194/cp-7-1041-2011 https://cp.copernicus.org/articles/7/1041/2011/ eng eng info:eu-repo/grantAgreement/EC/FP7/243908 doi:10.5194/cp-7-1041-2011 https://cp.copernicus.org/articles/7/1041/2011/ info:eu-repo/semantics/openAccess eISSN: 1814-9332 info:eu-repo/semantics/Text 2018 ftcopernicus https://doi.org/10.5194/cp-7-1041-2011 2020-07-20T16:26:01Z The sensitivity of interglacial Greenland temperature to orbital and CO 2 forcing is investigated using the NorthGRIP ice core data and coupled ocean-atmosphere IPSL-CM4 model simulations. These simulations were conducted in response to different interglacial orbital configurations, and to increased CO 2 concentrations. These different forcings cause very distinct simulated seasonal and latitudinal temperature and water cycle changes, limiting the analogies between the last interglacial and future climate. However, the IPSL-CM4 model shows similar magnitudes of Arctic summer warming and climate feedbacks in response to 2 × CO 2 and orbital forcing of the last interglacial period (126 000 years ago). The IPSL-CM4 model produces a remarkably linear relationship between TOA incoming summer solar radiation and simulated changes in summer and annual mean central Greenland temperature. This contrasts with the stable isotope record from the Greenland ice cores, showing a multi-millennial lagged response to summer insolation. During the early part of interglacials, the observed lags may be explained by ice sheet-ocean feedbacks linked with changes in ice sheet elevation and the impact of meltwater on ocean circulation, as investigated with sensitivity studies. A quantitative comparison between ice core data and climate simulations requires stability of the stable isotope – temperature relationship to be explored. Atmospheric simulations including water stable isotopes have been conducted with the LMDZiso model under different boundary conditions. This set of simulations allows calculation of a temporal Greenland isotope-temperature slope (0.3–0.4‰ per °C) during warmer-than-present Arctic climates, in response to increased CO 2 , increased ocean temperature and orbital forcing. This temporal slope appears half as large as the modern spatial gradient and is consistent with other ice core estimates. It may, however, be model-dependent, as indicated by preliminary comparison with other models. This suggests that further simulations and detailed inter-model comparisons are also likely to be of benefit. Comparisons with Greenland ice core stable isotope data reveals that IPSL-CM4/LMDZiso simulations strongly underestimate the amplitude of the ice core signal during the last interglacial, which could reach +8–10 °C at fixed-elevation. While the model-data mismatch may result from missing positive feedbacks (e.g. vegetation), it could also be explained by a reduced elevation of the central Greenland ice sheet surface by 300–400 m. Other/Unknown Material Arctic Greenland Greenland ice core Greenland ice cores ice core Ice Sheet Copernicus Publications: E-Journals Arctic Greenland Climate of the Past 7 3 1041 1059 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The sensitivity of interglacial Greenland temperature to orbital and CO 2 forcing is investigated using the NorthGRIP ice core data and coupled ocean-atmosphere IPSL-CM4 model simulations. These simulations were conducted in response to different interglacial orbital configurations, and to increased CO 2 concentrations. These different forcings cause very distinct simulated seasonal and latitudinal temperature and water cycle changes, limiting the analogies between the last interglacial and future climate. However, the IPSL-CM4 model shows similar magnitudes of Arctic summer warming and climate feedbacks in response to 2 × CO 2 and orbital forcing of the last interglacial period (126 000 years ago). The IPSL-CM4 model produces a remarkably linear relationship between TOA incoming summer solar radiation and simulated changes in summer and annual mean central Greenland temperature. This contrasts with the stable isotope record from the Greenland ice cores, showing a multi-millennial lagged response to summer insolation. During the early part of interglacials, the observed lags may be explained by ice sheet-ocean feedbacks linked with changes in ice sheet elevation and the impact of meltwater on ocean circulation, as investigated with sensitivity studies. A quantitative comparison between ice core data and climate simulations requires stability of the stable isotope – temperature relationship to be explored. Atmospheric simulations including water stable isotopes have been conducted with the LMDZiso model under different boundary conditions. This set of simulations allows calculation of a temporal Greenland isotope-temperature slope (0.3–0.4‰ per °C) during warmer-than-present Arctic climates, in response to increased CO 2 , increased ocean temperature and orbital forcing. This temporal slope appears half as large as the modern spatial gradient and is consistent with other ice core estimates. It may, however, be model-dependent, as indicated by preliminary comparison with other models. This suggests that further simulations and detailed inter-model comparisons are also likely to be of benefit. Comparisons with Greenland ice core stable isotope data reveals that IPSL-CM4/LMDZiso simulations strongly underestimate the amplitude of the ice core signal during the last interglacial, which could reach +8–10 °C at fixed-elevation. While the model-data mismatch may result from missing positive feedbacks (e.g. vegetation), it could also be explained by a reduced elevation of the central Greenland ice sheet surface by 300–400 m. |
format |
Other/Unknown Material |
author |
Masson-Delmotte, V. Braconnot, P. Hoffmann, G. Jouzel, J. Kageyama, M. Landais, A. Lejeune, Q. Risi, C. Sime, L. Sjolte, J. Swingedouw, D. Vinther, B. |
spellingShingle |
Masson-Delmotte, V. Braconnot, P. Hoffmann, G. Jouzel, J. Kageyama, M. Landais, A. Lejeune, Q. Risi, C. Sime, L. Sjolte, J. Swingedouw, D. Vinther, B. Sensitivity of interglacial Greenland temperature and δ18O: ice core data, orbital and increased CO2 climate simulations |
author_facet |
Masson-Delmotte, V. Braconnot, P. Hoffmann, G. Jouzel, J. Kageyama, M. Landais, A. Lejeune, Q. Risi, C. Sime, L. Sjolte, J. Swingedouw, D. Vinther, B. |
author_sort |
Masson-Delmotte, V. |
title |
Sensitivity of interglacial Greenland temperature and δ18O: ice core data, orbital and increased CO2 climate simulations |
title_short |
Sensitivity of interglacial Greenland temperature and δ18O: ice core data, orbital and increased CO2 climate simulations |
title_full |
Sensitivity of interglacial Greenland temperature and δ18O: ice core data, orbital and increased CO2 climate simulations |
title_fullStr |
Sensitivity of interglacial Greenland temperature and δ18O: ice core data, orbital and increased CO2 climate simulations |
title_full_unstemmed |
Sensitivity of interglacial Greenland temperature and δ18O: ice core data, orbital and increased CO2 climate simulations |
title_sort |
sensitivity of interglacial greenland temperature and δ18o: ice core data, orbital and increased co2 climate simulations |
publishDate |
2018 |
url |
https://doi.org/10.5194/cp-7-1041-2011 https://cp.copernicus.org/articles/7/1041/2011/ |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic Greenland Greenland ice core Greenland ice cores ice core Ice Sheet |
genre_facet |
Arctic Greenland Greenland ice core Greenland ice cores ice core Ice Sheet |
op_source |
eISSN: 1814-9332 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/243908 doi:10.5194/cp-7-1041-2011 https://cp.copernicus.org/articles/7/1041/2011/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/cp-7-1041-2011 |
container_title |
Climate of the Past |
container_volume |
7 |
container_issue |
3 |
container_start_page |
1041 |
op_container_end_page |
1059 |
_version_ |
1766336586052534272 |