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| Titel |
Contrasting roles of interception and transpiration in the hydrological cycle – Part 2: Moisture recycling |
| VerfasserIn |
R. J. van der Ent, L. Wang-Erlandsson, P. W. Keys, H. H. G. Savenije |
| 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 ; 5, no. 2 ; Nr. 5, no. 2 (2014-12-05), S.471-489 |
| Datensatznummer |
250115377
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| Publikation (Nr.) |
 copernicus.org/esd-5-471-2014.pdf |
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| Zusammenfassung |
| The contribution of land evaporation to local and remote precipitation (i.e.
moisture recycling) is of significant importance to sustain water resources
and ecosystems. But how important are different evaporation components in
sustaining precipitation? This is the first paper to present moisture
recycling metrics for partitioned evaporation. In the companion paper
Wang-Erlandsson et al. (2014) (hereafter Part 1), evaporation was partitioned into
vegetation interception, floor interception, soil moisture evaporation and
open-water evaporation (constituting the direct, purely physical fluxes,
largely dominated by interception), and transpiration (delayed, biophysical
flux). Here, we track these components forward as well as backward in time.
We also include age tracers to study the atmospheric residence times of these
evaporation components. We present a new image of the global hydrological
cycle that includes quantification of partitioned evaporation and moisture
recycling as well as the atmospheric residence times of all fluxes. We
demonstrate that evaporated interception is more likely to return as
precipitation on land than transpired water. On average, direct evaporation
(essentially interception) is found to have an atmospheric residence time of
8 days, while transpiration typically resides for 9 days in the atmosphere.
The process scale over which evaporation recycles is more local for
interception compared to transpiration; thus interception generally
precipitates closer to its evaporative source than transpiration, which is
particularly pronounced outside the tropics. We conclude that interception
mainly works as an intensifier of the local hydrological cycle during wet
spells and wet seasons. On the other hand, transpiration remains active
during dry spells and dry seasons and is transported over much larger
distances downwind, where it can act as a significant source of moisture.
Thus, as various land-use types can differ considerably in their partitioning
between interception and transpiration, our results stress that land-use
changes (e.g. forest-to-cropland conversion) do not only affect the magnitude
of moisture recycling, but could also influence the moisture recycling
patterns and lead to a redistribution of water resources. As such, this
research highlights that land-use changes can have complex effects on the
atmospheric branch of the hydrological cycle. |
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