The role of greenhouse gases in past climatic variations : an approach based on accurate chronologies of deep polar ice cores
Deep polar ice cores contain records of both past climate and trapped air that reflects past atmospheric compositions, notably of greenhouse gases. This record allows us to investigate the role of greenhouse gases in climate variations over eight glacial-interglacial cycles. The ice core record, lik...
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Online Access: | https://theses.hal.science/tel-02450783 https://theses.hal.science/tel-02450783/document https://theses.hal.science/tel-02450783/file/BEEMAN_2019_diffusion.pdf |
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ftunivnantes:oai:HAL:tel-02450783v1 2023-05-15T13:32:30+02:00 The role of greenhouse gases in past climatic variations : an approach based on accurate chronologies of deep polar ice cores Le rôle des gaz à effet de serre dans les variations climatiques passées : une approche basée sur des chronologies précises des forages polaires profonds Beeman, Jai Chowdhry Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ) Université Grenoble Alpes Frédéric Parrenin Amaëlle Landais Emmanuel Witrant 2019-10-21 https://theses.hal.science/tel-02450783 https://theses.hal.science/tel-02450783/document https://theses.hal.science/tel-02450783/file/BEEMAN_2019_diffusion.pdf en eng HAL CCSD NNT: 2019GREAU023 tel-02450783 https://theses.hal.science/tel-02450783 https://theses.hal.science/tel-02450783/document https://theses.hal.science/tel-02450783/file/BEEMAN_2019_diffusion.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-02450783 Climatology. Université Grenoble Alpes, 2019. English. ⟨NNT : 2019GREAU023⟩ Glaciology Paleoclimatology Dating Greenhouse gases Automation Bayesian methods Glaciologie Paleoclimatologie Datation Gaz à effet de serre Automatisation Méthodes bayésiennes [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology info:eu-repo/semantics/doctoralThesis Theses 2019 ftunivnantes 2023-03-08T04:55:21Z Deep polar ice cores contain records of both past climate and trapped air that reflects past atmospheric compositions, notably of greenhouse gases. This record allows us to investigate the role of greenhouse gases in climate variations over eight glacial-interglacial cycles. The ice core record, like all paleoclimate records, contains uncertainties associated both with the relationships between proxies and climate variables, and with the chronologies of the records contained in the ice and trapped air bubbles. In this thesis, we develop a framework, based on Bayesian inverse modeling and the evaluation of complex probability densities, to accurately treat uncertainty in the ice core paleoclimate record. Using this framework, we develop two studies, the first about Antarctic Temperature and CO2 during the last deglaciation, and the second developing a Bayesian synchronization method for ice cores. In the first study, we use inverse modeling to identify the probabilities of piecewise linear fits to CO2 and a stack of Antarctic Temperature records from five ice cores, along with the individual temperature records from each core, over the last deglacial warming, known as Termination 1. Using the nodes, or change points in the piecewise linear fits accepted during the stochastic sampling of the posterior probability density, we discuss the timings of millenial-scale changes in trend in the series, and calculate the phasings between coherent changes. We find that the phasing between Antarctic Temperature and CO2 likely varied, though the response times remain within a range of ~500 years from synchrony, both between events during the deglaciation and accross the individual ice core records. This result indicates both regional-scale complexity and modulations or variations in the mechanisms linking Antarctic temperature and CO2 accross the deglaciation. In the second study, we develop a Bayesian method to synchronize ice cores using corresponding time series in the IceChrono inverse chronological model. Tests show that ... Doctoral or Postdoctoral Thesis Antarc* Antarctic ice core Université de Nantes: HAL-UNIV-NANTES Antarctic |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
Glaciology Paleoclimatology Dating Greenhouse gases Automation Bayesian methods Glaciologie Paleoclimatologie Datation Gaz à effet de serre Automatisation Méthodes bayésiennes [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
spellingShingle |
Glaciology Paleoclimatology Dating Greenhouse gases Automation Bayesian methods Glaciologie Paleoclimatologie Datation Gaz à effet de serre Automatisation Méthodes bayésiennes [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology Beeman, Jai Chowdhry The role of greenhouse gases in past climatic variations : an approach based on accurate chronologies of deep polar ice cores |
topic_facet |
Glaciology Paleoclimatology Dating Greenhouse gases Automation Bayesian methods Glaciologie Paleoclimatologie Datation Gaz à effet de serre Automatisation Méthodes bayésiennes [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
description |
Deep polar ice cores contain records of both past climate and trapped air that reflects past atmospheric compositions, notably of greenhouse gases. This record allows us to investigate the role of greenhouse gases in climate variations over eight glacial-interglacial cycles. The ice core record, like all paleoclimate records, contains uncertainties associated both with the relationships between proxies and climate variables, and with the chronologies of the records contained in the ice and trapped air bubbles. In this thesis, we develop a framework, based on Bayesian inverse modeling and the evaluation of complex probability densities, to accurately treat uncertainty in the ice core paleoclimate record. Using this framework, we develop two studies, the first about Antarctic Temperature and CO2 during the last deglaciation, and the second developing a Bayesian synchronization method for ice cores. In the first study, we use inverse modeling to identify the probabilities of piecewise linear fits to CO2 and a stack of Antarctic Temperature records from five ice cores, along with the individual temperature records from each core, over the last deglacial warming, known as Termination 1. Using the nodes, or change points in the piecewise linear fits accepted during the stochastic sampling of the posterior probability density, we discuss the timings of millenial-scale changes in trend in the series, and calculate the phasings between coherent changes. We find that the phasing between Antarctic Temperature and CO2 likely varied, though the response times remain within a range of ~500 years from synchrony, both between events during the deglaciation and accross the individual ice core records. This result indicates both regional-scale complexity and modulations or variations in the mechanisms linking Antarctic temperature and CO2 accross the deglaciation. In the second study, we develop a Bayesian method to synchronize ice cores using corresponding time series in the IceChrono inverse chronological model. Tests show that ... |
author2 |
Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ) Université Grenoble Alpes Frédéric Parrenin Amaëlle Landais Emmanuel Witrant |
format |
Doctoral or Postdoctoral Thesis |
author |
Beeman, Jai Chowdhry |
author_facet |
Beeman, Jai Chowdhry |
author_sort |
Beeman, Jai Chowdhry |
title |
The role of greenhouse gases in past climatic variations : an approach based on accurate chronologies of deep polar ice cores |
title_short |
The role of greenhouse gases in past climatic variations : an approach based on accurate chronologies of deep polar ice cores |
title_full |
The role of greenhouse gases in past climatic variations : an approach based on accurate chronologies of deep polar ice cores |
title_fullStr |
The role of greenhouse gases in past climatic variations : an approach based on accurate chronologies of deep polar ice cores |
title_full_unstemmed |
The role of greenhouse gases in past climatic variations : an approach based on accurate chronologies of deep polar ice cores |
title_sort |
role of greenhouse gases in past climatic variations : an approach based on accurate chronologies of deep polar ice cores |
publisher |
HAL CCSD |
publishDate |
2019 |
url |
https://theses.hal.science/tel-02450783 https://theses.hal.science/tel-02450783/document https://theses.hal.science/tel-02450783/file/BEEMAN_2019_diffusion.pdf |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic ice core |
genre_facet |
Antarc* Antarctic ice core |
op_source |
https://theses.hal.science/tel-02450783 Climatology. Université Grenoble Alpes, 2019. English. ⟨NNT : 2019GREAU023⟩ |
op_relation |
NNT: 2019GREAU023 tel-02450783 https://theses.hal.science/tel-02450783 https://theses.hal.science/tel-02450783/document https://theses.hal.science/tel-02450783/file/BEEMAN_2019_diffusion.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766027463633141760 |