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| Titel |
Quantifying energy and water fluxes in dry dune ecosystems of the Netherlands |
| VerfasserIn |
B. R. Voortman, R. P. Bartholomeus, S. E. A. T. M. van der Zee, M. F. P. Bierkens, J. P. M. Witte |
| 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 ; 19, no. 9 ; Nr. 19, no. 9 (2015-09-08), S.3787-3805 |
| Datensatznummer |
250120803
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| Publikation (Nr.) |
 copernicus.org/hess-19-3787-2015.pdf |
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| Zusammenfassung |
| Coastal and inland dunes provide various ecosystem services that are related
to groundwater, such as drinking water production and biodiversity. To manage
groundwater in a sustainable manner, knowledge of actual evapotranspiration
(ETa) for the various land covers in dunes is essential. Aiming
at improving the parameterization of dune vegetation in hydrometeorological
models, this study explores the magnitude of energy and water fluxes in an
inland dune ecosystem in the Netherlands. Hydrometeorological measurements
were used to parameterize the Penman–Monteith evapotranspiration model for
four different surfaces: bare sand, moss, grass and heather. We found that
the net longwave radiation (Rnl) was the largest energy flux for
most surfaces during daytime. However, modeling this flux by a calibrated
FAO-56 Rnl model for each surface and for hourly time steps was
unsuccessful. Our Rnl model, with a novel submodel using solar
elevation angle and air temperature to describe the diurnal pattern in
radiative surface temperature, improved Rnl simulations
considerably. Model simulations of evaporation from moss surfaces showed that
the modulating effect of mosses on the water balance is species-dependent. We
demonstrate that dense moss carpets (Campylopus introflexus)
evaporate more (5 %, +14 mm) than bare sand (total of
258 mm in 2013), while more open-structured mosses (Hypnum
cupressiforme) evaporate less (−30 %, −76 mm) than bare
sand. Additionally, we found that a drought event in the summer of 2013
showed a pronounced delayed signal on lysimeter measurements of
ETa for the grass and heather surfaces, respectively. Due to the
desiccation of leaves after the drought event, and their feedback on the
surface resistance, the potential evapotranspiration in the year 2013 dropped
by 9 % (−37 mm) and 10 % (−61 mm) for the grass
and heather surfaces, respectively, which subsequently led to lowered
ETa of 8 % (−29 mm) and 7 % (−29 mm).
These feedbacks are of importance for water resources, especially during a
changing climate with an increasing number of drought days. Therefore, such
feedbacks need to be integrated into a coupled plant physiological and
hydrometeorological model to accurately simulate ETa. In
addition, our study showed that groundwater recharge in dunes can be
increased considerably by promoting moss vegetation, especially of open-structured moss species. |
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