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| Titel |
Quantifying the thermodynamic entropy budget of the land surface: is this useful? |
| VerfasserIn |
N. A. Brunsell, S. J. Schymanski, A. Kleidon |
| 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 ; 2, no. 1 ; Nr. 2, no. 1 (2011-06-20), S.87-103 |
| Datensatznummer |
250000462
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| Publikation (Nr.) |
 copernicus.org/esd-2-87-2011.pdf |
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| Zusammenfassung |
| As a system is moved away from a state of thermodynamic equilibrium, spatial
and temporal heterogeneity is induced. A possible methodology to assess these
impacts is to examine the thermodynamic entropy budget and assess the role of
entropy production and transfer between the surface and the atmosphere. Here,
we adopted this thermodynamic framework to examine the implications of
changing vegetation fractional cover on land surface energy exchange
processes using the NOAH land surface model and eddy covariance observations.
Simulations that varied the relative fraction of vegetation were used to
calculate the resultant entropy budget as a function of fraction of
vegetation. Results showed that increasing vegetation fraction increases
entropy production by the land surface while decreasing the overall entropy
budget (the rate of change in entropy at the surface). This is accomplished
largely via simultaneous increase in the entropy production associated with
the absorption of solar radiation and a decline in the Bowen ratio (ratio of
sensible to latent heat flux), which leads to increasing the entropy export
associated with the latent heat flux during the daylight hours and dominated
by entropy transfer associated with sensible heat and soil heat fluxes during
the nighttime hours. Eddy covariance observations also show that the entropy
production has a consistent sensitivity to land cover, while the overall
entropy budget appears most related to the net radiation at the surface,
however with a large variance. This implies that quantifying the
thermodynamic entropy budget and entropy production is a useful metric for
assessing biosphere-atmosphere-hydrosphere system interactions. |
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