EVALUATION OF SATELLITE-BASED RAINFALL ESTIMATES AND ITS APPLICATION IN MONITORING METEOROLOGICAL DROUGHT OVER NIGERIA

Abstract

The satellite rainfall products have different performance in different geographical regions under different physical and climatic condition. The overarching goal of this study is to assess the accuracy of remotely sensed precipitation products and its application in monitoring meteorological drought over Nigeria basin. The satellite rainfall product used in this study was selected through evaluating the performance of six operational high-resolution products (CHIRPS, PERSIANN, TRMM, TAMSAT, ERA, and GPCC). The statistical performance measuring techniques used include (Pearson correlation coefficient (r), mean error (ME), root means square error (RMSE), and bias) were used to evaluate the satellite rainfall products with corresponding weather surface data at twenty-five independent weather stations for a period of thirty years from 1984 – 2013, the thirty years’ data was divided in three decades. The evaluation result of these satellite derived rainfall products shows that GPCC had the best correlation then CHIRPS, PERSIANN, TRMM, TAMSAT, and ERA. Thus, the GPCC rainfall product was selected and used in monitoring meteorological drought over Nigeria, the SPI was used in the study to classified drought severity. Moreover, moderate dry zone, severed dry zone were observed in some part of the study area. Hence GPCC rainfall product can be used as an alternative source of information in dealing with water system such flood, erosion and other rainfall related disaster, for early warning system