ABSTRACT
The impact-based combined drought index (CDI) is defined in the thesis as a drought index that optimally combines the information embedded in other drought indices for monitoring a certain impact of drought. Developing the impact-based CDI was done through assigning weights to the individual drought indices using random search optimisation. Lastly the same approach for developing an impact-based CDI and crop-yield anomaly models was applied using drought indices based on Earth Observation data. The developed Earth Observation-based combined drought index (EO-CDI), showed its potential to characterize the drought conditions in the basin. The EO-CDI indicated negative or positive crop yield anomalies correctly for a majority of the years. The developed impact-based CDIs and multiple linear regression models have shown to be effective tools in indicating historic drought events in the Upper Blue Nile. The chapter also presents an overview of the key concepts discussed in this book.
