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| Titel |
Vertical and horizontal processes in the global atmosphere and the maximum entropy production conjecture |
| VerfasserIn |
S. Pascale, J. M. Gregory, M. H. P. Ambaum, R. Tailleux, V. Lucarini |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2190-4979
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| Digitales Dokument |
URL |
| Erschienen |
In: Earth System Dynamics ; 3, no. 1 ; Nr. 3, no. 1 (2012-01-19), S.19-32 |
| Datensatznummer |
250000847
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| Publikation (Nr.) |
 copernicus.org/esd-3-19-2012.pdf |
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| Zusammenfassung |
| The objective of this paper is to reconsider the Maximum Entropy Production
conjecture (MEP) in the context of a very simple two-dimensional
zonal-vertical climate model able to represent the total material entropy
production due at the same time to both horizontal and vertical heat fluxes.
MEP is applied first to a simple four-box model of climate which accounts for
both horizontal and vertical material heat fluxes. It is shown that, under
condition of fixed insolation, a MEP solution is found with reasonably
realistic temperature and heat fluxes, thus generalising results from
independent two-box horizontal or vertical models. It is also shown that the
meridional and the vertical entropy production terms are independently
involved in the maximisation and thus MEP can be applied to each subsystem
with fixed boundary conditions. We then extend the four-box model by
increasing its resolution, and compare it with GCM output. A MEP solution is
found which is fairly realistic as far as the horizontal large scale
organisation of the climate is concerned whereas the vertical structure looks
to be unrealistic and presents seriously unstable features. This study
suggest that the thermal meridional structure of the atmosphere is predicted
fairly well by MEP once the insolation is given but the vertical structure of
the atmosphere cannot be predicted satisfactorily by MEP unless constraints
are imposed to represent the determination of longwave absorption by
water vapour and clouds as a function of the state of the climate.
Furthermore an order-of-magnitude estimate of contributions to the material
entropy production due to horizontal and vertical processes within the
climate system is provided by using two different methods. In both cases we
found that approximately 40 mW m−2 K−1 of material entropy
production is due to vertical heat transport and 5–7 mW m−2 K−1
to horizontal heat transport. |
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