Joint Seminar: Bistability of the Atlantic subpolar gyre in a coarse-resolution climate model
The dynamics of the Nordic Seas and the subpolar gyre is crucial for
deep water formation and overturning circulation in the
Atlantic. During past decades significant changes in ocean properties have been
observed.Here we show that large-scale dynamics, as captured by coarse resolution
climate models, allows for a bistability of the Atlantic subpolar gyre.
We suggest three positive feedbacks which yield the necessary
nonlinearity for this behavior. Transitions between the two states can
be triggered by small fluctuations in surface freshwater flux to the
Nordic Seas, only slightly larger than natural variability presently
observed in the region.
Date
28.02.2007
Time
13:30 h
Place
- Bundesstr. 53, room 022/023
- Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg
Speaker
Anders Levermann, Potsdam Institute for Climate Impact Reasearch