IceChrono1: a probabilistic model to compute a common and optimal chronology for several ice cores
Polar ice cores provide exceptional archives of past environmental conditions. The dating of ice cores and the estimation of the age-scale uncertainty are essential to interpret the climate and environmental records that they contain. It is, however, a complex problem which involves different method...
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ftdoajarticles:oai:doaj.org/article:955143560a8e42e6887bd4595cf91791 2023-05-15T13:37:06+02:00 IceChrono1: a probabilistic model to compute a common and optimal chronology for several ice cores F. Parrenin L. Bazin E. Capron A. Landais B. Lemieux-Dudon V. Masson-Delmotte 2015-05-01T00:00:00Z https://doi.org/10.5194/gmd-8-1473-2015 https://doaj.org/article/955143560a8e42e6887bd4595cf91791 EN eng Copernicus Publications http://www.geosci-model-dev.net/8/1473/2015/gmd-8-1473-2015.pdf https://doaj.org/toc/1991-959X https://doaj.org/toc/1991-9603 1991-959X 1991-9603 doi:10.5194/gmd-8-1473-2015 https://doaj.org/article/955143560a8e42e6887bd4595cf91791 Geoscientific Model Development, Vol 8, Iss 5, Pp 1473-1492 (2015) Geology QE1-996.5 article 2015 ftdoajarticles https://doi.org/10.5194/gmd-8-1473-2015 2022-12-31T07:25:48Z Polar ice cores provide exceptional archives of past environmental conditions. The dating of ice cores and the estimation of the age-scale uncertainty are essential to interpret the climate and environmental records that they contain. It is, however, a complex problem which involves different methods. Here, we present IceChrono1, a new probabilistic model integrating various sources of chronological information to produce a common and optimized chronology for several ice cores, as well as its uncertainty. IceChrono1 is based on the inversion of three quantities: the surface accumulation rate, the lock-in depth (LID) of air bubbles and the thinning function. The chronological information integrated into the model are models of the sedimentation process (accumulation of snow, densification of snow into ice and air trapping, ice flow), ice- and air-dated horizons, ice and air depth intervals with known durations, Δdepth observations (depth shift between synchronous events recorded in the ice and in the air) and finally air and ice stratigraphic links in between ice cores. The optimization is formulated as a least squares problem, implying that all densities of probabilities are assumed to be Gaussian. It is numerically solved using the Levenberg–Marquardt algorithm and a numerical evaluation of the model's Jacobian. IceChrono follows an approach similar to that of the Datice model which was recently used to produce the AICC2012 (Antarctic ice core chronology) for four Antarctic ice cores and one Greenland ice core. IceChrono1 provides improvements and simplifications with respect to Datice from the mathematical, numerical and programming point of views. The capabilities of IceChrono1 are demonstrated on a case study similar to the AICC2012 dating experiment. We find results similar to those of Datice, within a few centuries, which is a confirmation of both IceChrono1 and Datice codes. We also test new functionalities with respect to the original version of Datice: observations as ice intervals with known durations, ... Article in Journal/Newspaper Antarc* Antarctic Greenland Greenland ice core ice core Directory of Open Access Journals: DOAJ Articles Antarctic Greenland Geoscientific Model Development 8 5 1473 1492 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Geology QE1-996.5 |
spellingShingle |
Geology QE1-996.5 F. Parrenin L. Bazin E. Capron A. Landais B. Lemieux-Dudon V. Masson-Delmotte IceChrono1: a probabilistic model to compute a common and optimal chronology for several ice cores |
topic_facet |
Geology QE1-996.5 |
description |
Polar ice cores provide exceptional archives of past environmental conditions. The dating of ice cores and the estimation of the age-scale uncertainty are essential to interpret the climate and environmental records that they contain. It is, however, a complex problem which involves different methods. Here, we present IceChrono1, a new probabilistic model integrating various sources of chronological information to produce a common and optimized chronology for several ice cores, as well as its uncertainty. IceChrono1 is based on the inversion of three quantities: the surface accumulation rate, the lock-in depth (LID) of air bubbles and the thinning function. The chronological information integrated into the model are models of the sedimentation process (accumulation of snow, densification of snow into ice and air trapping, ice flow), ice- and air-dated horizons, ice and air depth intervals with known durations, Δdepth observations (depth shift between synchronous events recorded in the ice and in the air) and finally air and ice stratigraphic links in between ice cores. The optimization is formulated as a least squares problem, implying that all densities of probabilities are assumed to be Gaussian. It is numerically solved using the Levenberg–Marquardt algorithm and a numerical evaluation of the model's Jacobian. IceChrono follows an approach similar to that of the Datice model which was recently used to produce the AICC2012 (Antarctic ice core chronology) for four Antarctic ice cores and one Greenland ice core. IceChrono1 provides improvements and simplifications with respect to Datice from the mathematical, numerical and programming point of views. The capabilities of IceChrono1 are demonstrated on a case study similar to the AICC2012 dating experiment. We find results similar to those of Datice, within a few centuries, which is a confirmation of both IceChrono1 and Datice codes. We also test new functionalities with respect to the original version of Datice: observations as ice intervals with known durations, ... |
format |
Article in Journal/Newspaper |
author |
F. Parrenin L. Bazin E. Capron A. Landais B. Lemieux-Dudon V. Masson-Delmotte |
author_facet |
F. Parrenin L. Bazin E. Capron A. Landais B. Lemieux-Dudon V. Masson-Delmotte |
author_sort |
F. Parrenin |
title |
IceChrono1: a probabilistic model to compute a common and optimal chronology for several ice cores |
title_short |
IceChrono1: a probabilistic model to compute a common and optimal chronology for several ice cores |
title_full |
IceChrono1: a probabilistic model to compute a common and optimal chronology for several ice cores |
title_fullStr |
IceChrono1: a probabilistic model to compute a common and optimal chronology for several ice cores |
title_full_unstemmed |
IceChrono1: a probabilistic model to compute a common and optimal chronology for several ice cores |
title_sort |
icechrono1: a probabilistic model to compute a common and optimal chronology for several ice cores |
publisher |
Copernicus Publications |
publishDate |
2015 |
url |
https://doi.org/10.5194/gmd-8-1473-2015 https://doaj.org/article/955143560a8e42e6887bd4595cf91791 |
geographic |
Antarctic Greenland |
geographic_facet |
Antarctic Greenland |
genre |
Antarc* Antarctic Greenland Greenland ice core ice core |
genre_facet |
Antarc* Antarctic Greenland Greenland ice core ice core |
op_source |
Geoscientific Model Development, Vol 8, Iss 5, Pp 1473-1492 (2015) |
op_relation |
http://www.geosci-model-dev.net/8/1473/2015/gmd-8-1473-2015.pdf https://doaj.org/toc/1991-959X https://doaj.org/toc/1991-9603 1991-959X 1991-9603 doi:10.5194/gmd-8-1473-2015 https://doaj.org/article/955143560a8e42e6887bd4595cf91791 |
op_doi |
https://doi.org/10.5194/gmd-8-1473-2015 |
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Geoscientific Model Development |
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8 |
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5 |
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1473 |
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1492 |
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