What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores?
Ice-core-based records of isotopic composition are a proxy for past temperatures and can thus provide information on polar climate variability over a large range of timescales. However, individual isotope records are affected by a multitude of processes that may mask the true temperature variability...
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ftdoajarticles:oai:doaj.org/article:7a9481b19d3c400daf7c643ee70014bd 2023-05-15T13:37:07+02:00 What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores? T. Münch T. Laepple 2018-12-01T00:00:00Z https://doi.org/10.5194/cp-14-2053-2018 https://doaj.org/article/7a9481b19d3c400daf7c643ee70014bd EN eng Copernicus Publications https://www.clim-past.net/14/2053/2018/cp-14-2053-2018.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-14-2053-2018 1814-9324 1814-9332 https://doaj.org/article/7a9481b19d3c400daf7c643ee70014bd Climate of the Past, Vol 14, Pp 2053-2070 (2018) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2018 ftdoajarticles https://doi.org/10.5194/cp-14-2053-2018 2022-12-31T07:26:19Z Ice-core-based records of isotopic composition are a proxy for past temperatures and can thus provide information on polar climate variability over a large range of timescales. However, individual isotope records are affected by a multitude of processes that may mask the true temperature variability. The relative magnitude of climate and non-climate contributions is expected to vary as a function of timescale, and thus it is crucial to determine those temporal scales on which the actual signal dominates the noise. At present, there are no reliable estimates of this timescale dependence of the signal-to-noise ratio (SNR). Here, we present a simple method that applies spectral analyses to stable-isotope data from multiple cores to estimate the SNR, and the signal and noise variability, as a function of timescale. The method builds on separating the contributions from a common signal and from local variations and includes a correction for the effects of diffusion and time uncertainty. We apply our approach to firn-core arrays from Dronning Maud Land (DML) in East Antarctica and from the West Antarctic Ice Sheet (WAIS). For DML and decadal to multi-centennial timescales, we find an increase in the SNR by nearly 1 order of magnitude ( ∼ 0.2 at decadal and ∼ 1.0 at multi-centennial scales). The estimated spectrum of climate variability also shows increasing variability towards longer timescales, contrary to what is traditionally inferred from single records in this region. In contrast, the inferred variability spectrum for WAIS stays close to constant over decadal to centennial timescales, and the results even suggest a decrease in SNR over this range of timescales. We speculate that these differences between DML and WAIS are related to differences in the spatial and temporal scales of the isotope signal, highlighting the potentially more homogeneous atmospheric conditions on the Antarctic Plateau in contrast to the marine-influenced conditions on WAIS. In general, our approach provides a methodological basis for ... Article in Journal/Newspaper Antarc* Antarctic Antarctica DML Dronning Maud Land East Antarctica ice core Ice Sheet Directory of Open Access Journals: DOAJ Articles Antarctic The Antarctic East Antarctica Dronning Maud Land West Antarctic Ice Sheet Climate of the Past 14 12 2053 2070 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 T. Münch T. Laepple What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores? |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
Ice-core-based records of isotopic composition are a proxy for past temperatures and can thus provide information on polar climate variability over a large range of timescales. However, individual isotope records are affected by a multitude of processes that may mask the true temperature variability. The relative magnitude of climate and non-climate contributions is expected to vary as a function of timescale, and thus it is crucial to determine those temporal scales on which the actual signal dominates the noise. At present, there are no reliable estimates of this timescale dependence of the signal-to-noise ratio (SNR). Here, we present a simple method that applies spectral analyses to stable-isotope data from multiple cores to estimate the SNR, and the signal and noise variability, as a function of timescale. The method builds on separating the contributions from a common signal and from local variations and includes a correction for the effects of diffusion and time uncertainty. We apply our approach to firn-core arrays from Dronning Maud Land (DML) in East Antarctica and from the West Antarctic Ice Sheet (WAIS). For DML and decadal to multi-centennial timescales, we find an increase in the SNR by nearly 1 order of magnitude ( ∼ 0.2 at decadal and ∼ 1.0 at multi-centennial scales). The estimated spectrum of climate variability also shows increasing variability towards longer timescales, contrary to what is traditionally inferred from single records in this region. In contrast, the inferred variability spectrum for WAIS stays close to constant over decadal to centennial timescales, and the results even suggest a decrease in SNR over this range of timescales. We speculate that these differences between DML and WAIS are related to differences in the spatial and temporal scales of the isotope signal, highlighting the potentially more homogeneous atmospheric conditions on the Antarctic Plateau in contrast to the marine-influenced conditions on WAIS. In general, our approach provides a methodological basis for ... |
format |
Article in Journal/Newspaper |
author |
T. Münch T. Laepple |
author_facet |
T. Münch T. Laepple |
author_sort |
T. Münch |
title |
What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores? |
title_short |
What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores? |
title_full |
What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores? |
title_fullStr |
What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores? |
title_full_unstemmed |
What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores? |
title_sort |
what climate signal is contained in decadal- to centennial-scale isotope variations from antarctic ice cores? |
publisher |
Copernicus Publications |
publishDate |
2018 |
url |
https://doi.org/10.5194/cp-14-2053-2018 https://doaj.org/article/7a9481b19d3c400daf7c643ee70014bd |
geographic |
Antarctic The Antarctic East Antarctica Dronning Maud Land West Antarctic Ice Sheet |
geographic_facet |
Antarctic The Antarctic East Antarctica Dronning Maud Land West Antarctic Ice Sheet |
genre |
Antarc* Antarctic Antarctica DML Dronning Maud Land East Antarctica ice core Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica DML Dronning Maud Land East Antarctica ice core Ice Sheet |
op_source |
Climate of the Past, Vol 14, Pp 2053-2070 (2018) |
op_relation |
https://www.clim-past.net/14/2053/2018/cp-14-2053-2018.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-14-2053-2018 1814-9324 1814-9332 https://doaj.org/article/7a9481b19d3c400daf7c643ee70014bd |
op_doi |
https://doi.org/10.5194/cp-14-2053-2018 |
container_title |
Climate of the Past |
container_volume |
14 |
container_issue |
12 |
container_start_page |
2053 |
op_container_end_page |
2070 |
_version_ |
1766088177398841344 |