Developing new drought indices with and without climate signal information over the Upper Blue Nile

Abstract

The Upper Blue Nile region in Ethiopia, frequently affected by drought conditions and much of its water flows from high land regions to territorial countries. Hence to characterize, monitor and forecast drought, an advanced drought index which considers the combination of different climatic conditions in this region is required. The main objective of this article is to develop new drought indices by considering with and without climate signal contribution which is precious in decision mak ing of policy makers and scientific community. In order to estimate the quality and performance of the developed indices we implemented statistical methods of RMSE, MAE and bias with the existing index of SPI across different time scales. Infact we developed two drought indices by considering SST into the meteorological variables (MVDIstS) and without considering SST (MVDIst0). Both drought indices show drought severity, larger duration than that of SPI.