Sea ice feedbacks influence the isotopic signature of Greenland ice sheet elevation changes: last interglacial HadCM3 simulations
<p>Changes in the Greenland ice sheet (GIS) affect global sea level. Greenland stable water isotope (<span class="inline-formula"><i>δ</i><sup>18</sup>O</span>) records from ice cores offer information on past changes in the surface of the GIS. Her...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2020-12-01
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| Series: | Climate of the Past |
| Online Access: | https://cp.copernicus.org/articles/16/2485/2020/cp-16-2485-2020.pdf |
| _version_ | 1818601033847275520 |
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| author | I. Malmierca-Vallet I. Malmierca-Vallet L. C. Sime P. J. Valdes J. C. Tindall |
| author_facet | I. Malmierca-Vallet I. Malmierca-Vallet L. C. Sime P. J. Valdes J. C. Tindall |
| author_sort | I. Malmierca-Vallet |
| collection | DOAJ |
| description | <p>Changes in the Greenland ice sheet (GIS) affect global sea level. Greenland stable water isotope (<span class="inline-formula"><i>δ</i><sup>18</sup>O</span>) records from ice cores offer information on past changes in the surface of the GIS. Here, we use the isotope-enabled Hadley Centre Coupled Model version 3 (HadCM3) climate model to simulate a set of last interglacial (LIG) idealised GIS surface elevation change scenarios focusing on GIS ice core sites. We investigate how <span class="inline-formula"><i>δ</i><sup>18</sup>O</span> depends on the magnitude and sign of GIS elevation change and evaluate how the response is altered by sea ice changes. We find that modifying GIS elevation induces changes in Northern Hemisphere atmospheric circulation, sea ice and precipitation patterns. These climate feedbacks lead to ice-core-averaged isotopic lapse rates of 0.49 ‰ (100 m)<span class="inline-formula"><sup>−1</sup></span> for the lowered GIS states and 0.29 ‰ (100 m)<span class="inline-formula"><sup>−1</sup></span> for the enlarged GIS states. This is lower than the spatially derived Greenland lapse rates of 0.62–0.72 ‰ (100 m)<span class="inline-formula"><sup>−1</sup></span>. These results thus suggest non-linearities in the isotope–elevation relationship and have consequences for the interpretation of past elevation and climate changes across Greenland. In particular, our results suggest that winter sea ice changes may significantly influence isotope–elevation gradients: winter sea ice effect can decrease (increase) modelled core-averaged isotopic lapse rate values by about <span class="inline-formula">−</span>19 % (and <span class="inline-formula">+</span>28 %) for the lowered (enlarged) GIS states, respectively. The largest influence of sea ice on <span class="inline-formula"><i>δ</i><sup>18</sup>O</span> changes is found in coastal regions like the Camp Century site.</p> |
| first_indexed | 2024-12-16T12:44:57Z |
| format | Article |
| id | doaj.art-f8b116bd7ba94037a621b9c6b3a2d9e9 |
| institution | Directory Open Access Journal |
| issn | 1814-9324 1814-9332 |
| language | English |
| last_indexed | 2024-12-16T12:44:57Z |
| publishDate | 2020-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj.art-f8b116bd7ba94037a621b9c6b3a2d9e92022-12-21T22:31:19ZengCopernicus PublicationsClimate of the Past1814-93241814-93322020-12-01162485250810.5194/cp-16-2485-2020Sea ice feedbacks influence the isotopic signature of Greenland ice sheet elevation changes: last interglacial HadCM3 simulationsI. Malmierca-Vallet0I. Malmierca-Vallet1L. C. Sime2P. J. Valdes3J. C. Tindall4British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UKSchool of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS, UKBritish Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UKSchool of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS, UKSchool of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK<p>Changes in the Greenland ice sheet (GIS) affect global sea level. Greenland stable water isotope (<span class="inline-formula"><i>δ</i><sup>18</sup>O</span>) records from ice cores offer information on past changes in the surface of the GIS. Here, we use the isotope-enabled Hadley Centre Coupled Model version 3 (HadCM3) climate model to simulate a set of last interglacial (LIG) idealised GIS surface elevation change scenarios focusing on GIS ice core sites. We investigate how <span class="inline-formula"><i>δ</i><sup>18</sup>O</span> depends on the magnitude and sign of GIS elevation change and evaluate how the response is altered by sea ice changes. We find that modifying GIS elevation induces changes in Northern Hemisphere atmospheric circulation, sea ice and precipitation patterns. These climate feedbacks lead to ice-core-averaged isotopic lapse rates of 0.49 ‰ (100 m)<span class="inline-formula"><sup>−1</sup></span> for the lowered GIS states and 0.29 ‰ (100 m)<span class="inline-formula"><sup>−1</sup></span> for the enlarged GIS states. This is lower than the spatially derived Greenland lapse rates of 0.62–0.72 ‰ (100 m)<span class="inline-formula"><sup>−1</sup></span>. These results thus suggest non-linearities in the isotope–elevation relationship and have consequences for the interpretation of past elevation and climate changes across Greenland. In particular, our results suggest that winter sea ice changes may significantly influence isotope–elevation gradients: winter sea ice effect can decrease (increase) modelled core-averaged isotopic lapse rate values by about <span class="inline-formula">−</span>19 % (and <span class="inline-formula">+</span>28 %) for the lowered (enlarged) GIS states, respectively. The largest influence of sea ice on <span class="inline-formula"><i>δ</i><sup>18</sup>O</span> changes is found in coastal regions like the Camp Century site.</p>https://cp.copernicus.org/articles/16/2485/2020/cp-16-2485-2020.pdf |
| spellingShingle | I. Malmierca-Vallet I. Malmierca-Vallet L. C. Sime P. J. Valdes J. C. Tindall Sea ice feedbacks influence the isotopic signature of Greenland ice sheet elevation changes: last interglacial HadCM3 simulations Climate of the Past |
| title | Sea ice feedbacks influence the isotopic signature of Greenland ice sheet elevation changes: last interglacial HadCM3 simulations |
| title_full | Sea ice feedbacks influence the isotopic signature of Greenland ice sheet elevation changes: last interglacial HadCM3 simulations |
| title_fullStr | Sea ice feedbacks influence the isotopic signature of Greenland ice sheet elevation changes: last interglacial HadCM3 simulations |
| title_full_unstemmed | Sea ice feedbacks influence the isotopic signature of Greenland ice sheet elevation changes: last interglacial HadCM3 simulations |
| title_short | Sea ice feedbacks influence the isotopic signature of Greenland ice sheet elevation changes: last interglacial HadCM3 simulations |
| title_sort | sea ice feedbacks influence the isotopic signature of greenland ice sheet elevation changes last interglacial hadcm3 simulations |
| url | https://cp.copernicus.org/articles/16/2485/2020/cp-16-2485-2020.pdf |
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