Estimation of pixel-scale daily rainfall over Nile River catchments using multi-spectral METEOSAT data.

Visible, infrared and water vapour data from METEOSAT are used in a multi-spectral methodology to estimate small-scale daily rainfall over the Nile River basin. Rainy areas are first delineated every half hour and then daily linear regression is used to estimate daily rainfall amounts from half-hourly delineated areas and observed daily raingauge rainfall. Validation tests of the consistency of the rainfall estimates were based on reproduction of spatial averages over large domains of the Nile River and temporal averages at raingauge sites. Use with a distributed hydrological model for the Blue Nile basin with outlet at Diem, Sudan, shows good performance in simulating daily flows. The methodology is used at the Nile Forecast Center in Cairo as part of the operational Nile Forecast System.