Evaluation of five satellite products for estimation of rainfall over Uganda

Five satellite-based rainfall estimation algorithms (TRMM 3B42, CMORPH, TAMSAT, RFE 2.0 and PERSIANN) are assessed against historical monthly rainfall statistics from raingauges within four regions of Uganda. Results are discussed in terms of the accuracy of the products, the effect of climate variability, and differences between products. Products are able to reasonably reflect seasonal patterns in rainfall, and also the spatial patterns in rainfall between regions. Patterns in the Occurrence of rainfall are better reflected than patterns in rainfall amounts. There is significant scope for improving the estimation of amounts by calibration to the raingauge data. TRMM 3B42, CMORPH and TAMSAT show most promise in this application followed by RFE 2.0 and the PERSIANN system. However, the relative performance of the products depends on what aspects of the rainfall regime are being considered. Differences between the products are large and the use of more than one product for any application is recommended.