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W. G. Pritchard Lab Seminar: 11:15 AM - 12:15 PM, 106 McAllister Bldg

	              **Monday October 30, 2006**
	
Halocline catastrophes and other such matters

John S. Wettlaufer

Dept of Geophysics
Yale University


Abstract:

Recently one finds it difficult to pick up a newspaper or magazine without 
finding reference to global warming driving the melting of ice in the 
polar regions.  Nonetheless, present observations cannot be placed 
properly within the context of trend versus fluctuation, and all 
predictions of future disaster derive from enormously complex and highly 
tuned Global Climate Models.  We take a different approach and use fluid 
mechanics, laboratory experiments and idealized theory to investigate the 
two principal settings that may drive relatively abrupt changes in the 
polar ice cover: the ventilation of the cold halocline, which traps warm 
water with a stable salinity stratification, and the underlying 
sensitivity of ice cover to changes in albedo.  Despite the apparent 
simplicity, the approach has value in that it allows one to constrain the 
necessary conditions for catastrophic changes and hence provide 
information for those searching for clues within the complexity of large 
scale models.

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