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| Titel |
Evaluation of satellite rainfall estimates over Ethiopian river basins |
| VerfasserIn |
T. G. Romilly, M. Gebremichael |
| 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. 5 ; Nr. 15, no. 5 (2011-05-19), S.1505-1514 |
| Datensatznummer |
250012785
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| Publikation (Nr.) |
 copernicus.org/hess-15-1505-2011.pdf |
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| Zusammenfassung |
| High resolution satellite-based rainfall estimates (SREs) have enormous
potential for use in hydrological applications, particularly in the
developing world as an alternative to conventional rain gauges which are
typically sparse. In this study, three SREs have been evaluated against
collocated rain gauge measurements in Ethiopia across six river basins that
represent different rainfall regimes and topography. The comparison is made
using five-year (2003–2007) averages, and results are stratified by river
basin, elevation and season. The SREs considered are: the Climate Prediction
Center morphing method (CMORPH), Precipitation Estimation from Remotely
Sensed Information Using Neural Networks (PERSIANN) and the real-time
version of the Tropical Rainfall Measuring Mission (TRMM) Multisatellite
Precipitation Analysis (TMPA) 3B42RT. Overall, the microwave-based products
TMPA 3B42RT and CMORPH outperform the infrared-based product PERSIANN:
PERSIANN tends to underestimate rainfall by 43 %, while CMORPH tends to
underestimate by 11 % and TMPA 3B42RT tends to overestimate by 5 %. The
bias in the satellite rainfall estimates depends on the rainfall regime,
and, in some regimes, the elevation. In the northwest region, which is
characterized mainly by highland topography, a humid climate and a strong
Intertropical Convergence Zone (ITCZ) effect, elevation has a strong
influence on the accuracy of the SREs: TMPA 3B42RT and CMORPH tend to
overestimate at low elevations but give reasonably accurate results at high
elevations, whereas PERSIANN gives reasonably accurate values at low
elevations but underestimates at high elevations. In the southeast region,
which is characterized mainly by lowland topography, a semi-arid climate and
southerly winds, elevation does not have a significant influence on the
accuracy of the SREs, and all the SREs underestimate rainfall across almost
all elevations. |
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