EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Evaluating atmospheric simulations of the Last Glacial Maximum using oxygen isotopes in ice cores and speleothems

André Paul1, Thejna Tharammal2, Alexandre Cauquoin3,4, and Martin Werner4
André Paul et al.
  • 1University of Bremen, MARUM - Center for Marine Environmental Sciences, Department of Geosciences, Bremen, Germany (
  • 2Center for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore, India
  • 3Institute of Industrial Science, The University of Tokyo, Kashiwa, Chiba, Japan
  • 4Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Bremerhaven, Germany

Our goal is to investigate the structural uncertainty in the isotope-enabled atmospheric general circulation models iCAM5 and ECHAM6-wiso. In order to reduce all other sources of uncertainties, in particular, those that stem from different boundary conditions, we forced the two models by the same sets of pre-industrial (PI) and Last Glacial Maximum (LGM) surface boundary conditions; the latter were taken from GLOMAP  (Paul et al., 2021), which in turn were based on the MARGO project (MARGO Project Members, 2009) and recent estimates of LGM sea-ice extent. We compared our model results to reconstructions from ice cores (cf. Risi et al., 2010) and speleothems (cf. Comas-Bru et al., 2020). This comparison showed to what degree realizations of the atmospheric state of the LGM obtained from different models, due to different model set-ups and parameterizations, are in agreement with the proxy data. For example, the precipitation during the LGM was generally less depleted in the ECHAM6-wiso as compared to iCAM5, and as it turned out, the iCAM5 simulation produced only a rather weak LGM anomaly during summer (June-July-August, JJA) over the South Asian monsoon region.

How to cite: Paul, A., Tharammal, T., Cauquoin, A., and Werner, M.: Evaluating atmospheric simulations of the Last Glacial Maximum using oxygen isotopes in ice cores and speleothems, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5749,, 2022.

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