EGU22-766
https://doi.org/10.5194/egusphere-egu22-766
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

A new perspective on permafrost boundaries in France during the Last Glacial Maximum

Kim Helen Stadelmaier1, Patrick Ludwig1, Pascal Bertran2,3, Pierre Antoine4, Xiaoxu Shi5, Gerrit Lohmann5,6, and Joaquim G. Pinto1
Kim Helen Stadelmaier et al.
  • 1Institute of Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany (kim.stadelmaier@kit.edu)
  • 2Inrap, Bègles, France
  • 3PACEA, CNRS–Université de Bordeaux, Pessac, France
  • 4Laboratoire de Géographie Physique, CNRS, Meudon CEDEX, France
  • 5Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
  • 6MARUM and Institute of Environmental Physics, University of Bremen, Bremen, Germany

During the Last Glacial Maximum (LGM), a very cold and dry period around 26.5–19 kyr BP, permafrost was widespread across Europe. In this work, we explore the possible benefit of using regional climate model data to improve the permafrost representation in France, decipher how the atmospheric circulation affects the permafrost boundaries in the models, and test the role of ground thermal contraction cracking in wedge development during the LGM. With these aims, criteria for possible thermal contraction cracking of the ground are applied to climate model data for the first time. Our results show that the permafrost extent and ground cracking regions deviate from proxy evidence when the simulated large-scale circulation in both global and regional climate models favours prevailing westerly winds. A colder and, with regard to proxy data, more realistic version of the LGM climate is achieved given more frequent easterly winds conditions. Given the appropriate forcing, an added value of the regional climate model simulation can be achieved in representing permafrost and ground thermal contraction cracking. Furthermore, the model data provide evidence that thermal contraction cracking occurred in Europe during the LGM in a wide latitudinal band south of the probable permafrost border, in agreement with field data analysis. This enables the reconsideration of the role of sand-wedge casts to identify past permafrost regions.

How to cite: Stadelmaier, K. H., Ludwig, P., Bertran, P., Antoine, P., Shi, X., Lohmann, G., and Pinto, J. G.: A new perspective on permafrost boundaries in France during the Last Glacial Maximum, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-766, https://doi.org/10.5194/egusphere-egu22-766, 2022.

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