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Titel |
Thermodynamic constraints on effective energy and mass transfer and catchment function |
VerfasserIn |
C. Rasmussen |
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 ; 16, no. 3 ; Nr. 16, no. 3 (2012-03-06), S.725-739 |
Datensatznummer |
250013207
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Publikation (Nr.) |
copernicus.org/hess-16-725-2012.pdf |
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Zusammenfassung |
Understanding how water, energy and carbon are partitioned to primary
production and effective precipitation is central to quantifying the limits
on critical zone evolution. Recent work suggests quantifying energetic
transfers to the critical zone in the form of effective precipitation and
primary production provides a first order approximation of critical zone
process and structural organization. However, explicit linkage of this
effective energy and mass transfer (EEMT; W m−2) to critical zone state
variables and well defined physical limits remains to be developed. The
objective of this work was to place EEMT in the context of thermodynamic state
variables of temperature and vapor pressure deficit, with explicit
definition of EEMT physical limits using a global climate dataset. The relation
of EEMT to empirical measures of catchment function was also examined using a
subset of the Model Parameter Estimation Experiment (MOPEX) catchments. The
data demonstrated three physical limits for EEMT: (i) an absolute vapor pressure
deficit threshold of 1200 Pa above which EEMT is zero; (ii) a temperature
dependent vapor pressure deficit limit following the saturated vapor
pressure function up to a temperature of 292 K; and (iii) a minimum
precipitation threshold required from EEMT production at temperatures greater
than 292 K. Within these limits, EEMT scales directly with precipitation, with
increasing conversion of the precipitation to EEMT with increasing temperature.
The state-space framework derived here presents a simplified framework with
well-defined physical limits that has the potential for directly integrating
regional to pedon scale heterogeneity in effective energy and mass transfer
relative to critical zone structure and function within a common
thermodynamic framework. |
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