CENOZOIC ANTARCTIC GLACIATION: An Integrated Atmosphere - Ocean - Ice Sheet Model Approach

The widespread glaciation of Antarctica and the associated shift towards colder temperatures at the Eocene-Oligocene boundary (about 35 million years ago) represents one of the most fundamental reorganisations of global climate in the earth's history. During the same time, the opening of the Southern Ocean gateways, the Drake Passage and the Tasman Gateway, led to the formation of the Antarctic Circumpolar Current and hence to the isolation of the Antarctic continent. Apart from the oceanic regime, other global phenomena such as the declining atmospheric carbon dioxide concentration and the orbital configuration, contributed to the onset of a persistent Antarctic glaciation.

With this project we address the impact of each of these processes on the formation of the Antarctic Ice Sheet. We put special emphasis on the ocean circulation, latent heat transport as well as on ice sheet dynamics in an integrated modelling approach. Shifts in atmospheric circulation, temperature changes, and snow accumulation over Antarctica and their forcing factors will be analysed in detail. The identification of thresholds for the Antarctic ice sheet development will yield novel views for the interpretation of palaeoclimatic records at the Eocene-Oligocene transition.

An integrated asynchronous model cycle (IAMC), together with the Meteorological Institute of Hamburg University (Uni HH), will be created, where simulation results of different models (ocean, atmosphere, and ice sheet) are used as boundary and forcing quantities for the other models. Stand-alone experiments as well as the execution of the IAMC approach will be used for time slice and sensitivity experiments with all three models. Thresholds and a scientific measure will be established to quantify atmospheric circulation regimes in the global models that favour growth and decay of Antarctic land ice.

Model components:
• PlaSim/LSG: coupled AOGCM of intermediate complexity
• ECHAM5: high resolution AGCM to simulate ice sheet forcing fields
• IceMod: dynamical ice sheet model (Huybrechts 1993)

Scientists

Gerrit Lohmann
Alfred-Wegener-Institute Bremerhaven

Martin Butzin
Universität Bremen

Klaus Grosfeld
Alfred-Wegener-Institute Bremerhaven

Philippe Huybrechts
Alfred-Wegener-Institute Bremerhaven

Luisa Cristini
Alfred-Wegener-Institute Bremerhaven

Research areas

Circumpolar 60 – 90° South

Publications

Huybrechts P, 1993. Glaciological modelling of the late Cenozoic east Antarctic ice sheet: stability or dynamism?, Geografiska Annaler, 75A(4), 221-238.

Butzin M, Lohmann G, Bickert T, 2011. Miocene ocean circulation inferred from marine carbon cycle modeling combined with benthic isotope records. Paleoceanography, 26, PA1203. doi:10.1029/2009PA001901

Cristini L, Grosfeld K, Butzin M, Lohmann G, 2011. Influence of Drake Passage, orbital configuartion, and greenhouse gas on the Cenozoic Antarctic Ice Sheet: sensitivity experiments with an asynchronous coupled climate-ice sheet model. Palaeogeopgaphy, Palaeoclimatology, Palaeoecology. (manuscript under revision)

Stepanek C, Lohmann G, Butzin M, 2011. Numerical studies on the influcence of gateways on ocean circulation. Journal of Geophysical Research - Ocean. (manuscript re-submission)

Homepage

Find more about Cenozoic Antarctic Glaciation at our Homepage

Research funding organisation

German Research Foundation

Project number: LO-1372/2
Funding period: September 2006 - September 2009