Research and training network on understanding Deep icE corE Proxies to Infer past antarctiC climatE dynamics

Informations projet

DEEPICE

N° de convention de subvention: 955750

DOI

10.3030/955750

Projet clôturé

Date de signature de la CE 21 Août 2020

Date de début 1 Janvier 2021

Date de fin 31 Mars 2025

Financé au titre de

EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Coût total

€ 4 166 057,88

Contribution de l’UE

€ 4 166 057,88

4 166 057,88

Coordonné par

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
France

Periodic Reporting for period 2 - DEEPICE (Research and training network on understanding Deep icE corE Proxies to Infer past antarctiC climatE dynamics)

Période du rapport: 2023-01-01 au 2025-03-31

The study of past climates has already shown that the climate of Earth is in a perpetual stage of change but some major changes which took place in the past require more research to fully understand them, such as the Mid Pleistocene Transition (MPT) which still lacks explanation. During the MPT, between about 900,000 years and 1.2 Million years ago, the cyclicity of glacial/interglacial cycles changed from 40,000 to 100,000 years.
To better understand this major climatic change, Beyond EPICA project was launched with the aim of drilling and recovering ice from up to 1.5 Million years ago in Antarctica at Little Dome C. The analysis of the information contained in the ice core will enable the paleoclimate community to address major scientific questions on the role of ice-sheet size and atmospheric greenhouse gas concentrations on the dynamics of past climate changes and thus to better understand the MPT.

DEEPICE project will contribute to tackle these technical & scientific challenges with a consortium gathering expertise in instrumentation , statistical tools as well as glaciological and climatic modeling from 10 different countries. Benefitting from these complementary expertise, the project sets up an innovative training program allowing a new generation of researchers to acquire essential core and additional skills, as well as diverse soft skills.
The 15 DEEPICE ESRs will carry out their individual research projects with a focus on an analytical or modeling subject in a strong interdisciplinary and intersectoral environment keeping in mind the importance of a combined data-model approach and with an active participation in science mediation in the field of climate change.

The study of past climates through the analysis of archives like ice cores is key to understanding the way our climate system works and how it might change in the future. Improving the understanding of past climate events like the MPT, will help scientists to put recent changes in the atmosphere and climate into perspective and to provide a useful framework of paleoclimate data on which climate models can be based. This will enable us to improve climate models and thus better predict the future evolution of climate.

Regarding the technical innovation for deep ice core analysis side of the project, several PhD projects led to the ongoing development of new analytical and innovative techniques to analyse deep section of ice cores with the highest resolution possible and minimizing the amount of ice needed by allowing several analyses in a row on a same section, with micro-destruction techniques, as well as allowing the analysis of multiple impurities, organic and inorganic particles.

Regarding the quantification of processes responsible for the climate signal in the ice core, the different PhD projects related to this aspect contribute to better understanding the processes that can affect the climate signal, in different parts of the ice (very deep ice, basal ice, firn, surface snow) and for different types of information (interpretation of gas concentration, dating methods, surface and subsurface processes affecting proxies, changes in ice microstructure and air inclusions…). All the projects have been mainly focused on preparing the samples or observations to get the first datasets required to conduct analysis for a better understanding of the ongoing processes.

Concerning the modelling and statistical tools used for ice core-based climate reconstructions, the different PhD projects related to these tools will enable the development of new modeling and statistical tools that will be used for a better interpretation of the data collected through ice core analysis (in particular, water isotopes signal, dating of the ice and age-depth profiles, and glacial dynamics and orbital forcing influencing climate proxies contained in ice cores), and therefore will participate to improve ice core-based climate reconstructions. All the projects have been mainly focused on preparing the statistical tools and models that will be useful for the future analysis of deep ice core data, by either developing new model or adapting existing ones to integrate new functions and better resolution and producing the first sets of data. Some evaluations of the new model results with existing dataset have already been performed.

The techniques and instruments will enable high-resolution and multiple analysis consuming the minimal amount of ice possible, as these techniques will:
- enable high-resolution elemental analysis of single dust particles, with geochemical characterization of single dust particles in deep ice cores
- precisely quantify the fluctuation of ultra-trace elements like rare Earth elements in single particles
- enable analysis of organic compounds in ice cores with higher resolution
- allow to gain information on which new or unexplored organic compounds can be used as tracers of past climate,
- improve our understanding of the location and composition of dust particles in ice
- allow continuous analysis of ice crystals to better understand their relation to ice flow and ice deformation
- allow ultra high resolution of water isotopes in ice and hence ultra high temporal resolution of climate change recorded in ice cores

The project will also enable the acquisition of new climatic information, in particular for deep ice as well as better interpretation of existing proxies through a better understanding of the mechanisms affecting these proxies. In particular, this will contribute to:
- establishing corrected N2O record for long-time scale periods
- obtaining new types of information on past climate from the study of the properties of air hydrates
- developing new independant dating tools through innovative methods (study of air hydrates, radiometric dating with the 10Be/ 36Cl ratio) and improving existing dating tools by deciphering the different influences on the dO2/N2 record
- obtaining new data and developing knowledge of the processes taking place in the basal ice part of ice cores
- characterizing the process of bubble close-off at the site of Beyond EPICA ice core to better interpret climatic and environmental records in the gas phase of this ice core
- studying how surface and near-surface processes affect the climate signal recorded in water isotope in the ice core.

The modelling and statistical tools prepared will enable a better interpretation of ice core data, in particular by:
- optimizing the recovery method of water isotope record in deep ice cores by developing a statistical method to better estimate the diffusion length of stable water isotopes in the Dome C ice core, hence improving the temporal resolution at which climatic reconstruction can be inferred from water isotope record
- better quantifying associated uncertainties of isotope-temperature relation thanks to the development of isotope modelling capabilities of climate models that will foster our understanding of the climatic controls on Antarctic snowfall isotopic composition
- elaborating age-depth profiles with models on the basis of radar horizons, to predict the age and resolution of ice likely to be found at sites like the drilling site of Beyond EPICA
- elaborating models to investigate the ice sheet dynamics during MPT, and the role of orbital forcings to better understand the mechanisms behind the MPT

DEEPICE network

Periodic Reporting for period 2 - DEEPICE (Research and training network on understanding Deep icE corE Proxies to Infer past antarctiC climatE dynamics)

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