12.3
Application of entropy production extremal principles to simplified climate models
Takamitsu Ito, MIT, Cambridge, MA; and J. Marshall
We study idealized models of the global climate to examine the hypothesis
that the climate adjusts to a state of maximum entropy production, as first
discussed by Paltridge 1975. We develop a hierarchy of atmosphere,
ocean and coupled box models and maximize the climate entropy production
under the constraint of global energy balance. These are compared
to simplified, but dynamically based, climate models. Entropy production
is defined here as , where
,
is the meridional heat transport from one box to another, and
is the temperature of each box. The extremal solutions exhibit some
notable properties: (i) they are in plausible agreement with gross
measures (heat transport and pole-equator temperature difference) of the
present climate (ii) they are close to the extremal entropy production
states diagnosed from simplified climate models in which
is determined by detailed dynamics (iii) the simplicity of the models
allows us to fully investigate the sensitivity of climate entropy production
and its extremal state to model parameters.
Session 12, Large-scale dynamics of the coupled ocean-atmosphere system
Friday, 8 June 2001, 10:30 AM-12:05 PM
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Extended Abstract (44K)