Validation of Irain Products over Uganda

Abstract

Uganda and East Africa in general has experienced in the 2001 to 2011 period some of the worst drought and flood events to date, culminating in the high-impact drought of 2010/11. Long-term and timely monitoring of precipitation is thus essential, and satellite-based precipitation products can help in coping with the relatively sparse rain gauge ground networks of this area of the world. However, the complex topography and the marked geographic variability of precipitation in the region make precipitation retrieval from satellites problematic and product validation and inter-comparison necessary. Therefore, this study focused on the Validation Of iRain Products over Uganda for the period, 2000-2017. Monthly rainfall data was obtained from the official cite of iRain (CHRUS DATA) which was validated with ground data observations obtained from Uganda National Meteorological Authority. The methods employed were the spearman’s rank correlation, the bias analysis where the RMSE and ME were calculated and for the trend analysis where the trend graphs were plotted. From the results Gulu had the biggest correlation value also from the trend graphs, Gulu and Entebbe both show negative correlations while Kampala, Mbarara, Tororo and Jinja showed positive trends in observation data and negative trends in the satellite data. The study therefore concluded that the iRain products should be supplemented and validated with the ground observations.