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| Titel |
Building a field- and model-based climatology of local water and energy cycles in the cultivated Sahel – annual budgets and seasonality |
| VerfasserIn |
C. Velluet, J. Demarty, B. Cappelaere, I. Braud, H. B.-A. Issoufou, N. Boulain, D. Ramier, I. Mainassara, G. Charvet, M. Boucher, J.-P. Chazarin, M. Oi, H. Yahou, B. Maidaji, F. Arpin-Pont, N. Benarrosh, A. Mahamane, Y. Nazoumou, G. Favreau, J. Seghieri |
| 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 ; 18, no. 12 ; Nr. 18, no. 12 (2014-12-10), S.5001-5024 |
| Datensatznummer |
250120554
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| Publikation (Nr.) |
 copernicus.org/hess-18-5001-2014.pdf |
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| Zusammenfassung |
| In the sub-Saharan Sahel, energy and water cycling at the land surface is
pivotal for the regional climate, water resources and land productivity, yet it
is still very poorly documented. As a step towards a comprehensive
climatological description of surface fluxes in this area, this study
provides estimates of long-term average annual budgets and seasonal cycles
for two main land use types of the cultivated Sahelian belt: rainfed millet
crop and fallow bush. These estimates build on the combination of a 7-year
field data set from two typical plots in southwestern Niger with detailed
physically based soil–plant–atmosphere modeling, yielding a continuous,
comprehensive set of water and energy flux and storage variables over this
multiyear period. In the present case in particular, blending field data with
mechanistic modeling makes the best use of available data and knowledge for
the construction of the multivariate time series. Rather than using the
model only to gap-fill observations into a composite series, model–data
integration is generalized homogeneously over time by generating the whole
series with the entire data-constrained model simulation. Climatological
averages of all water and energy variables, with associated sampling
uncertainty, are derived at annual to sub-seasonal scales from the time
series produced. Similarities and differences in the two ecosystem behaviors
are highlighted. Mean annual evapotranspiration is found to represent
~82–85% of rainfall for both systems, but with different
soil evaporation/plant transpiration partitioning and different seasonal
distribution. The remainder consists entirely of runoff for the fallow,
whereas drainage and runoff stand in a 40–60% proportion for the millet
field. These results should provide a robust reference for the surface
energy- and water-related studies needed in this region. Their significance
and the benefits they gain from the innovative data–model integration
approach are thoroughly discussed. The model developed in this context has
the potential for reliable simulations outside the reported conditions,
including changing climate and land cover. |
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