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Climate Dynamics

, Volume 18, Issue 6, pp 455–473 | Cite as

Coupled climate modelling of ocean circulation changes during ice age inception

  •  K. Meissner
  •  R. Gerdes

Abstract.

Freshening of high latitude surface waters can change the large-scale oceanic transport of heat and salt. Consequently, atmospheric and sea ice perturbations over the deep water production sites excite a large-scale response establishing an oceanic "teleconnection" with time scales of years to centuries. To study these feedbacks, a coupled atmosphere-ocean-sea ice model consisting of a two dimensional atmospheric energy and moisture balance model (EMBM) coupled to a thermodynamic sea ice model and an ocean general circulation model is utilised. The coupled model reproduces many aspects of the present oceanic circulation. We also investigate the climate impact of changes in fresh water balance during an ice age initiation. In this experiment part of the precipitation over continents is stored within continental ice sheets. During the buildup of ice sheets the oceanic stratification in the North Atlantic is weakened by a reduced continental run-off leading to an enhanced thermohaline circulation. Under these conditions salinity is redistributed such that deep water is more saline than under present conditions. Once the ice sheets built up, we simulate an ice age climate without net fresh water storage on the continents. In this case the coupled model reproduces the shallow and weak overturning cell, an ice edge advance insulating the upper ocean, and many other aspects of the glacial circulation.

Keywords

Ocean General Circulation Model Ocean Circulation Change High Latitude Surface Deep Water Production Edge Advance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 2001

Authors and Affiliations

  •  K. Meissner
    • 1
  •  R. Gerdes
    • 2
  1. 1.Alfred Wegener Institute for Polar and Marine Research, Germany, now at the School of Earth and Ocean Sciences, University of Victoria, P O Box 3055, Stn CSC, Victoria, BC, V8W 3P6, Canada
  2. 2.Alfred Wegener Institute for Polar and Marine Research, Bussestr.24, D-27570 Bremerhaven, Germany

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