Accuracy of satellite rainfall estimates in the Blue Nile Basin: Lowland plain versus highland mountain

The demand for accurate satellite rainfall products is increasing particularly in Africa where ground‐based data are mostly unavailable, timely inaccessible, and unreliable. In this study, the accuracy of three widely used, near‐global, high‐resolution satellite rainfall products (CMORPH, TMPA‐RT v7...

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Bibliographic Details
Published in:Water resources research 2014-11, Vol.50 (11), p.8775-8790
Main Authors: Gebremichael, Mekonnen, Bitew, Menberu M., Hirpa, Feyera A., Tesfay, Gebrehiwot N.
Format: Article
Language:English
Subjects:
Blue Nile basin
complex terrain
Elevation
Freshwater
Meteorological satellites
Rain
Rain gauges
rainfall
Rainfall rate
River basins
satellite rainfall product
Satellites
validation
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Summary:The demand for accurate satellite rainfall products is increasing particularly in Africa where ground‐based data are mostly unavailable, timely inaccessible, and unreliable. In this study, the accuracy of three widely used, near‐global, high‐resolution satellite rainfall products (CMORPH, TMPA‐RT v7, TMPA‐RP v7), with a spatial resolution of 0.25° and a temporal resolution of 3 h, is assessed over the Blue Nile River Basin, a basin characterized by complex terrain and tropical monsoon. The assessment is made using relatively dense experimental networks of rain gauges deployed at two, 0.25° × 0.25°, sites that represent contrasting topographic features: lowland plain (mean elevation of 719 m.a.s.l.) and highland mountain (mean elevation of 2268 m.a.s.l.). The investigation period covers the summer seasons of 2012 and 2013. Compared to the highland mountain site, the lowland plain site exhibits marked extremes of rain intensity, higher mean rain intensity when it rains, lower frequency of rain occurrence, and smaller seasonal rainfall accumulation. All the satellite products considered tend to overestimate the mean rainfall rate at the lowland plain site, but underestimate it at the highland mountain site. The satellite products miss more rainfall at the highland mountain site than at the lowland plain site, and underestimate the heavy rain rates at both sites. Both sites have uncertainty (root mean square error) values greater than 100% for 3 h accumulations of
ISSN:0043-1397
1944-7973
DOI:10.1002/2013WR014500