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| Titel |
Present and past climate as a state of maximum entropy production |
| VerfasserIn |
Corentin Herbert, Didier Paillard |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250032097
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| Zusammenfassung |
| Earth climate is represented as a steady state in a simple atmosphere box model
with no explicit time dependence. The part traditionnally played by atmospheric
dynamics is here filled by a global thermodynamic constraint : assuming energy
balance, radiative fluxes are calculated explicitly while convective and advective
heat fluxes are adjusted to satisfy a maximum entropy production condition. Such
models have already been considered in the past. Present work extends the maximum
entropy principle to vertical convective fluxes, provides a physical derivation of
radiative coefficients that were previously introduced as ad hoc parameters and sets a
formal framework for future generalizations and experiments. This model uses
no a priori parametrization : radiative fluxes are treated in a sleek new fashion,
Net Exchange Formulation, which allows for computation of optical depths at an
arbitrary accuracy, and the remaining degrees of freedom are infered from entropy
maximization.
Zonal mean temperatures predicted for present climate lie in a satisfactory range, while
the shape of energy transfers fits observations qualitatively. Applications to past climates are
also considered, with a specific emphasis on the Last Glacial Maximum : the MEP results for
the LGM are compared to more conventional data from intermediate complexity models or
GCMs. |
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