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| Titel |
Parameterization of a bucket model for soil-vegetation-atmosphere modeling under seasonal climatic regimes |
| VerfasserIn |
N. Romano, M. Palladino, G. B. Chirico |
| 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 ; 15, no. 12 ; Nr. 15, no. 12 (2011-12-21), S.3877-3893 |
| Datensatznummer |
250013062
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| Publikation (Nr.) |
 copernicus.org/hess-15-3877-2011.pdf |
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| Zusammenfassung |
| We investigate the potential impact of accounting for seasonal variations in
the climatic forcing and using different methods to parameterize the soil
water content at field capacity on the water balance components computed by
a bucket model (BM). The single-layer BM of Guswa et al. (2002) is employed,
whereas the Richards equation (RE) based Soil Water Atmosphere Plant (SWAP)
model is used as a benchmark model. The results are analyzed for two
differently-textured soils and for some synthetic runs under real-like
seasonal weather conditions, using stochastically-generated daily rainfall
data for a period of 100 years. Since transient soil-moisture dynamics and
climatic seasonality play a key role in certain zones of the World, such as
in Mediterranean land areas, a specific feature of this study is to test the
prediction capability of the bucket model under a condition where seasonal
variations in rainfall are not in phase with the variations in plant
transpiration. Reference is made to a hydrologic year in which we have a
rainy period (starting 1 November and lasting 151 days) where vegetation is
basically assumed in a dormant stage, followed by a drier and rainless
period with a vegetation regrowth phase. Better agreement between BM and
RE-SWAP intercomparison results are obtained when BM is parameterized by a
field capacity value determined through the drainage method proposed by
Romano and Santini (2002). Depending on the vegetation regrowth or dormant
seasons, rainfall variability within a season results in transpiration
regimes and soil moisture fluctuations with distinctive features. During the
vegetation regrowth season, transpiration exerts a key control on soil water
budget with respect to rainfall. During the dormant season of vegetation,
the precipitation regime becomes an important climate forcing. Simulations
also highlight the occurrence of bimodality in the probability distribution
of soil moisture during the season when plants are dormant, reflecting that
soil, it being of coarser or finer texture, can be preferentially in either
wetter or drier states over this period. |
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