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| Titel |
New lessons on the Sudd hydrology learned from remote sensing and climate modeling |
| VerfasserIn |
Y. A. Mohamed, H. H. G. Savenije, W. G. M. Bastiaanssen, B. J. J. M. Hurk |
| 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 ; 10, no. 4 ; Nr. 10, no. 4 (2006-07-10), S.507-518 |
| Datensatznummer |
250008138
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| Publikation (Nr.) |
 copernicus.org/hess-10-507-2006.pdf |
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| Zusammenfassung |
| Despite its local and regional importance, hydro-meteorological data on the
Sudd (one of Africa's largest wetlands) is very scanty. This is due to the
physical and political situation of this area of Sudan. The areal size of
the wetland, the evaporation rate, and the influence on the micro and meso
climate are still unresolved questions of the Sudd hydrology.
The evaporation flux from the Sudd wetland has been estimated using thermal
infrared remote sensing data and a parameterization of the surface energy
balance (SEBAL model). It is concluded that the actual spatially averaged
evaporation from the Sudd wetland over 3 years of different
hydrometeorological characteristics varies between 1460 and 1935 mm/yr. This
is substantially less than open water evaporation. The wetland area appears
to be 70% larger than previously assumed when the Sudd was considered as
an open water body. The temporal analysis of the Sudd evaporation
demonstrated that the variation of the atmospheric demand in combination
with the inter-annual fluctuation of the groundwater table results into a
quasi-constant evaporation rate in the Sudd, while open water evaporation
depicts a clear seasonal variability. The groundwater table characterizes a
distinct seasonality, confirming that substantial parts of the Sudd are
seasonal swamps.
The new set of spatially distributed evaporation parameters from remote
sensing form an important dataset for calibrating a regional climate model
enclosing the Nile Basin. The Regional Atmospheric Climate Model (RACMO)
provides an insight not only into the temporal evolution of the
hydro-climatological parameters, but also into the land surface climate
interactions and embedded feedbacks. The impact of the flooding of the Sudd
on the Nile hydroclimatology has been analysed by simulating two land
surface scenarios (with and without the Sudd wetland). The paper presents
some of the model results addressing the Sudd's influence on rainfall,
evaporation and runoff of the river Nile, as well as the influence on the
microclimate.
The paper presents a case study that confirms the feasibility of using
remote sensing data (with good spatial and poor temporal coverage) in
conjunction with a regional climate model. The combined model provides good
temporal and spatial representation in a region characterized by extremely
scarce ground data. |
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