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Titel |
Thermodynamic limits of hydrologic cycling within the Earth system: concepts, estimates and implications |
VerfasserIn |
A. Kleidon, M. Renner |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 17, no. 7 ; Nr. 17, no. 7 (2013-07-23), S.2873-2892 |
Datensatznummer |
250018942
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Publikation (Nr.) |
copernicus.org/hess-17-2873-2013.pdf |
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Zusammenfassung |
The hydrologic cycle results from the combination of energy conversions and
atmospheric transport, and the laws of thermodynamics set limits to both.
Here, we apply thermodynamics to derive the limits of the strength of
hydrologic cycling within the Earth system and about the properties and
processes that shape these limits. We set up simple models to derive
analytical expressions of the limits of evaporation and precipitation in
relation to vertical and horizontal differences in solar radiative forcing.
These limits result from a fundamental trade-off by which a greater
evaporation rate reduces the temperature gradient and thus the driver for
atmospheric motion that exchanges moistened air from the surface with the
drier air aloft. The limits on hydrologic cycling thus reflect the strong
interaction between the hydrologic flux, motion, and the driving gradient.
Despite the simplicity of the models, they yield estimates for the limits of
hydrologic cycling that are within the observed magnitude, suggesting that
the global hydrologic cycle operates near its maximum strength. We close with
a discussion of how thermodynamic limits can provide a better
characterization of the interaction of vegetation and human activity with
hydrologic cycling. |
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