Université de Strasbourg

Olaf Eisen

Biography - Olaf Eisen

Alfred Wegener Institute, Helmholtz-Centre for Polar and Marine Research and University of Bremen, Germany & USIAS Fellow at the Strasbourg Institute for Earth and Environment (ITES), University of Strasbourg and CNRS, France

Olaf Eisen, USIAS Fellow 2021 (Photographer: B. Rost, copyright CC-BY-SA-NC)

Olaf Eisen has been working in the field of cryospheric sciences since 1996, and became a joint professor for glaciology at the Alfred Wegener Institute (AWI) and the University of Bremen in 2014, co-leading the Section of Glaciology. He received his diploma in geophysics at the University of Karlsruhe in 1999 and his PhD from the University of Bremen in 2003 (both in Germany). During his university studies and postdoc time he spent several years abroad, at the University of Alaska (Fairbanks, USA) and the ETH Zürich, Switzerland. As a leader of a “young investigators research group” of the German Research Foundation’s Emmy Noether programme, which ran from 2008 to 2013 jointly at AWI and the Institute of Environmental Physics of the University of Heidelberg, he habilitated in 2010 in physics and became an adjunct professor in 2013. Professor Eisen acted as the president of the European Geosciences Union’s Division on Cryospheric Sciences from 2017 to 2021 and is co-editor-in-chief of the leading disciplinary journal The Cryosphere, where he is responsible for ice sheets. From 2016 to 2019 he was the coordinator of the first phase of the EU-funded project “Beyond EPICA – Oldest Ice”, leading the pre-site survey of the upcoming European deep drilling in Antarctica.

Over the course of his academic career he engaged in the analysis, modelling and interpretation of near-surface geophysical data and Earth's system compartments in numerous geoscientific research areas and engaged in interaction with the public to transfer scientific knowledge, e.g. through various blogs and public presentations.

During his Fellowship, Olaf Eisen will be welcomed by Dr. Dimitri Zigone at the Strasbourg Institute for Earth and Environment (ITES).

Project - Characterising ice-sheet properties and processes with novel seismic monitoring technology

01/10/2021 - 30/09/2023

The evolution of the Antarctic mass balance, i.e. the difference between snow falling on its surface and melting of ice shelves or calving of icebergs at its borders, is of utmost importance for the future sea level all around the world, especially also in Europe. The Antarctic ice sheet will play a major role for global sea level rise caused by global climate heating in the decades and centuries to come. However, Antarctic climate and mass balance have been highlighted as key sources of uncertainty when accurately predicting the future climate system and sea level, i.e. putting more exact numbers on the expected contribution to sea level rise. To date, significant challenges remain in understanding and representing the dynamics of the Antarctic ice sheets. At the same time, the ice sheet is a unique archive of the paleo atmosphere, which helps to better understand details of our climate system. Both aspects, correctly estimating future sea-level contributions and obtaining a reliable paleo-climate archive, rely on understanding the physical processes that control ice-sheet evolution over time. Two major uncertainties, which require further observations, are the mechanical properties within the ice sheet, and the characteristics of the ice sheet–bed interface. This USIAS project will establish new methodologies to obtain these observations and improve our knowledge of ice-sheet properties and dynamics. Our approach will be piloted at the EastGRIP ice-core drill site in Greenland and applied later during the EU-funded programme Beyond EPICA – Oldest Ice Core drilling in Antarctica, which aims to retrieve an ice core going back 1.5 million years.

We will employ three methodologies, which are new to glaciology. First, “Seismics While Drilling (SWD)” is a technique, which uses the noise created by a drill head during drilling as a source of seismic signals. Correlation of the seismic noise recorded at geophones, deployed at the surface, with the actual source signal from the drill head yields a classical seismic data set, from which physical properties can be deduced. This has never been demonstrated for ice-core drilling. Second, we will employ “Distributed Acoustic Sensing (DAS)”, an emerging seismological technique, which uses a standard fibre optic cable acting as a chain of sensors for seismic wavefield recording. In this project, we will go beyond previous approaches and aim to deploy a fibre optic cable in a liquid-filled 3 km deep borehole available after ice-core drilling. The goal is to improve previously possible characterizations of the distribution of physical properties, especially crystal orientation fabric. Third, we will use “Machine Learning (ML)” to establish up-to-date methods to improve the processing and analysis of the large data sets that will be acquired. We will adapt approaches already developed and implemented by the host group at ITES/EOST for seismological data sets, which will extend our capabilities to effectively exploit and interpret the results. The combination of all three methodologies above will yield new insights into the overall distribution of physical properties at a sufficiently high level to inform ice-flow models and improve the accuracy of model results.

Investissements d'Avenir