Climatic information archived in ice cores: impact of intermittency and diffusion on the recorded isotopic signal in Antarctica
The isotopic signal ( δ 18 O and δ D ) imprinted in ice cores from Antarctica is not solely generated by the temperature sensitivity of the isotopic composition of precipitation, but it also contains the signature of the intermittency of the precipitation patterns, as well as of post-deposition proc...
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ftcopernicus:oai:publications.copernicus.org:cp81464 2023-05-15T13:31:39+02:00 Climatic information archived in ice cores: impact of intermittency and diffusion on the recorded isotopic signal in Antarctica Casado, Mathieu Münch, Thomas Laepple, Thomas 2020-08-25 application/pdf https://doi.org/10.5194/cp-16-1581-2020 https://cp.copernicus.org/articles/16/1581/2020/ eng eng doi:10.5194/cp-16-1581-2020 https://cp.copernicus.org/articles/16/1581/2020/ eISSN: 1814-9332 Text 2020 ftcopernicus https://doi.org/10.5194/cp-16-1581-2020 2020-08-31T16:22:12Z The isotopic signal ( δ 18 O and δ D ) imprinted in ice cores from Antarctica is not solely generated by the temperature sensitivity of the isotopic composition of precipitation, but it also contains the signature of the intermittency of the precipitation patterns, as well as of post-deposition processes occurring at the surface and in the firn. This leads to a proxy signal recorded by the ice cores that may not be representative of the local climate variations. Due to precipitation intermittency, the ice cores only record brief snapshots of the climatic conditions, resulting in aliasing of the climatic signal and thus a large amount of noise which reduces the minimum temporal resolution at which a meaningful signal can be retrieved. The analyses are further complicated by isotopic diffusion, which acts as a low-pass filter that dampens any high-frequency changes. Here, we use reanalysis data (ERA-Interim) combined with satellite products of accumulation to evaluate the spatial distribution of the numerical estimates of the transfer function that describes the formation of the isotopic signal across Antarctica. As a result, the minimum timescales at which the signal-to-noise ratio exceeds unity range from less than 1 year at the coast to about 1000 years further inland. Based on solely physical processes, we are thus able to define a lower bound for the timescales at which climate variability can be reconstructed from the isotopic composition in ice cores. Text Antarc* Antarctica Copernicus Publications: E-Journals Climate of the Past 16 4 1581 1598 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
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The isotopic signal ( δ 18 O and δ D ) imprinted in ice cores from Antarctica is not solely generated by the temperature sensitivity of the isotopic composition of precipitation, but it also contains the signature of the intermittency of the precipitation patterns, as well as of post-deposition processes occurring at the surface and in the firn. This leads to a proxy signal recorded by the ice cores that may not be representative of the local climate variations. Due to precipitation intermittency, the ice cores only record brief snapshots of the climatic conditions, resulting in aliasing of the climatic signal and thus a large amount of noise which reduces the minimum temporal resolution at which a meaningful signal can be retrieved. The analyses are further complicated by isotopic diffusion, which acts as a low-pass filter that dampens any high-frequency changes. Here, we use reanalysis data (ERA-Interim) combined with satellite products of accumulation to evaluate the spatial distribution of the numerical estimates of the transfer function that describes the formation of the isotopic signal across Antarctica. As a result, the minimum timescales at which the signal-to-noise ratio exceeds unity range from less than 1 year at the coast to about 1000 years further inland. Based on solely physical processes, we are thus able to define a lower bound for the timescales at which climate variability can be reconstructed from the isotopic composition in ice cores. |
format |
Text |
author |
Casado, Mathieu Münch, Thomas Laepple, Thomas |
spellingShingle |
Casado, Mathieu Münch, Thomas Laepple, Thomas Climatic information archived in ice cores: impact of intermittency and diffusion on the recorded isotopic signal in Antarctica |
author_facet |
Casado, Mathieu Münch, Thomas Laepple, Thomas |
author_sort |
Casado, Mathieu |
title |
Climatic information archived in ice cores: impact of intermittency and diffusion on the recorded isotopic signal in Antarctica |
title_short |
Climatic information archived in ice cores: impact of intermittency and diffusion on the recorded isotopic signal in Antarctica |
title_full |
Climatic information archived in ice cores: impact of intermittency and diffusion on the recorded isotopic signal in Antarctica |
title_fullStr |
Climatic information archived in ice cores: impact of intermittency and diffusion on the recorded isotopic signal in Antarctica |
title_full_unstemmed |
Climatic information archived in ice cores: impact of intermittency and diffusion on the recorded isotopic signal in Antarctica |
title_sort |
climatic information archived in ice cores: impact of intermittency and diffusion on the recorded isotopic signal in antarctica |
publishDate |
2020 |
url |
https://doi.org/10.5194/cp-16-1581-2020 https://cp.copernicus.org/articles/16/1581/2020/ |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-16-1581-2020 https://cp.copernicus.org/articles/16/1581/2020/ |
op_doi |
https://doi.org/10.5194/cp-16-1581-2020 |
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Climate of the Past |
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16 |
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4 |
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1581 |
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1598 |
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1766019684578099200 |