EGU21-8383, updated on 14 Oct 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Model-data comparison in a strongly eddying Eocene ocean

Peter Nooteboom1,2, Michiel Baatsen1, Peter Bijl3, Erik van Sebille1,2, Appy Sluijs3, Henk Dijkstra1,2, and Anna von der Heydt1,2
Peter Nooteboom et al.
  • 1Utrecht University, IMAU, Department of Physics, Utrecht, Netherlands (
  • 2Centre for Complex Systems Studies, Utrecht University, Utrecht, Netherlands
  • 3Laboratory of Paleobotany and Palynology, Department of Earth Sciences, Utrecht University, Utrecht, Netherlands

Simulations of the geological past using General Circulation Models (GCMs) are computationally expensive. Mainly because of the long equilibration time scales, most of these GCMs have ocean components with a horizontal resolution of 1° or coarser. Such models are non-eddying and the effects of mesoscale ocean eddies on the transport of heat and salt are parameterized. However, from present-day ocean modeling studies, it is known that eddying ocean models better represent regional and time-mean ocean flows compared to non-eddying models. At the same time, proxy data from sediment sample sites represent climate at specific locations. Hence, the coarse ocean resolution of typical palaeo-GCMs lead to a challenge for model-data comparison in past climates.

Here we present the first simulations of a global eddying Eocene ocean with a 0.1° (horizontal) resolution model, which are initialized and forced with data from a coarser resolution (1° horizontally) equilibrated coupled ocean-atmosphere GCM. We investigate the response of the model equilibrium state to the change in ocean resolution and the consequences this has for model-data comparison in the middle-late Eocene (38Ma). We find that, compared to the non-eddying model, the eddying ocean resolution of palaeomodels reduce the biases in both sea surface temperatures and biogeographic patterns which are derived from proxy data.

How to cite: Nooteboom, P., Baatsen, M., Bijl, P., van Sebille, E., Sluijs, A., Dijkstra, H., and von der Heydt, A.: Model-data comparison in a strongly eddying Eocene ocean, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8383,, 2021.

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