Dating a tropical ice core by time–frequency analysis of ion concentration depth profiles
Ice core dating is a key parameter for the interpretation of the ice archives. However, the relationship between ice depth and ice age generally cannot be easily established and requires the combination of numerous investigations and/or modelling efforts. This paper presents a new approach to ice co...
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fttriple:oai:gotriple.eu:oai:doaj.org/article:68c830a7963d4ac38a6a81f458d3fea5 2023-05-15T16:38:46+02:00 Dating a tropical ice core by time–frequency analysis of ion concentration depth profiles M. Gay M. De Angelis J.-L. Lacoume 2014-09-01 https://doi.org/10.5194/cp-10-1659-2014 http://www.clim-past.net/10/1659/2014/cp-10-1659-2014.pdf https://doaj.org/article/68c830a7963d4ac38a6a81f458d3fea5 en eng Copernicus Publications 1814-9324 1814-9332 doi:10.5194/cp-10-1659-2014 http://www.clim-past.net/10/1659/2014/cp-10-1659-2014.pdf https://doaj.org/article/68c830a7963d4ac38a6a81f458d3fea5 undefined Climate of the Past, Vol 10, Iss 5, Pp 1659-1672 (2014) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2014 fttriple https://doi.org/10.5194/cp-10-1659-2014 2023-01-22T18:14:10Z Ice core dating is a key parameter for the interpretation of the ice archives. However, the relationship between ice depth and ice age generally cannot be easily established and requires the combination of numerous investigations and/or modelling efforts. This paper presents a new approach to ice core dating based on time–frequency analysis of chemical profiles at a site where seasonal patterns may be significantly distorted by sporadic events of regional importance, specifically at the summit area of Nevado Illimani (6350 m a.s.l.), located in the eastern Bolivian Andes (16°37' S, 67°46' W). We used ion concentration depth profiles collected along a 100 m deep ice core. The results of Fourier time–frequency and wavelet transforms were first compared. Both methods were applied to a nitrate concentration depth profile. The resulting chronologies were checked by comparison with the multi-proxy year-by-year dating published by de Angelis et al. (2003) and with volcanic tie points. With this first experiment, we demonstrated the efficiency of Fourier time–frequency analysis when tracking the nitrate natural variability. In addition, we were able to show spectrum aliasing due to under-sampling below 70 m. In this article, we propose a method of de-aliasing which significantly improves the core dating in comparison with annual layer manual counting. Fourier time–frequency analysis was applied to concentration depth profiles of seven other ions, providing information on the suitability of each of them for the dating of tropical Andean ice cores. Article in Journal/Newspaper ice core Unknown Climate of the Past 10 5 1659 1672 |
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geo envir M. Gay M. De Angelis J.-L. Lacoume Dating a tropical ice core by time–frequency analysis of ion concentration depth profiles |
topic_facet |
geo envir |
description |
Ice core dating is a key parameter for the interpretation of the ice archives. However, the relationship between ice depth and ice age generally cannot be easily established and requires the combination of numerous investigations and/or modelling efforts. This paper presents a new approach to ice core dating based on time–frequency analysis of chemical profiles at a site where seasonal patterns may be significantly distorted by sporadic events of regional importance, specifically at the summit area of Nevado Illimani (6350 m a.s.l.), located in the eastern Bolivian Andes (16°37' S, 67°46' W). We used ion concentration depth profiles collected along a 100 m deep ice core. The results of Fourier time–frequency and wavelet transforms were first compared. Both methods were applied to a nitrate concentration depth profile. The resulting chronologies were checked by comparison with the multi-proxy year-by-year dating published by de Angelis et al. (2003) and with volcanic tie points. With this first experiment, we demonstrated the efficiency of Fourier time–frequency analysis when tracking the nitrate natural variability. In addition, we were able to show spectrum aliasing due to under-sampling below 70 m. In this article, we propose a method of de-aliasing which significantly improves the core dating in comparison with annual layer manual counting. Fourier time–frequency analysis was applied to concentration depth profiles of seven other ions, providing information on the suitability of each of them for the dating of tropical Andean ice cores. |
format |
Article in Journal/Newspaper |
author |
M. Gay M. De Angelis J.-L. Lacoume |
author_facet |
M. Gay M. De Angelis J.-L. Lacoume |
author_sort |
M. Gay |
title |
Dating a tropical ice core by time–frequency analysis of ion concentration depth profiles |
title_short |
Dating a tropical ice core by time–frequency analysis of ion concentration depth profiles |
title_full |
Dating a tropical ice core by time–frequency analysis of ion concentration depth profiles |
title_fullStr |
Dating a tropical ice core by time–frequency analysis of ion concentration depth profiles |
title_full_unstemmed |
Dating a tropical ice core by time–frequency analysis of ion concentration depth profiles |
title_sort |
dating a tropical ice core by time–frequency analysis of ion concentration depth profiles |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://doi.org/10.5194/cp-10-1659-2014 http://www.clim-past.net/10/1659/2014/cp-10-1659-2014.pdf https://doaj.org/article/68c830a7963d4ac38a6a81f458d3fea5 |
genre |
ice core |
genre_facet |
ice core |
op_source |
Climate of the Past, Vol 10, Iss 5, Pp 1659-1672 (2014) |
op_relation |
1814-9324 1814-9332 doi:10.5194/cp-10-1659-2014 http://www.clim-past.net/10/1659/2014/cp-10-1659-2014.pdf https://doaj.org/article/68c830a7963d4ac38a6a81f458d3fea5 |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/cp-10-1659-2014 |
container_title |
Climate of the Past |
container_volume |
10 |
container_issue |
5 |
container_start_page |
1659 |
op_container_end_page |
1672 |
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1766029109515780096 |