Chapter 27 - Does using varying length of rainfall data affect assessment of drought in data scarce areas of Africa? A case study of Upper Blue Nile basin, Ethiopia

Abstract

In this study, we present an investigation of the spatial and temporal variation of meteorological droughts in the Upper Blue Nile (UBN) basin in Ethiopia using longer historical record (1952–2009) of 14 meteorological stations and 23 other stations with relatively shorter records (1975–2009). The influence of using varying record length on drought category was studied by comparing the Standard Precipitation Index (SPI) results from the 14 stations with long record length, by taking out incrementally 1year record from 1953 to 1975 and the same length of record was withheld incrementally at the middle of data length (1970–88). The results show that the record from 1953 to 2009 gave the same category of drought severity as that of drought category computed from 1975 to 2009 for each station. Moreover, the same result obtained for the data withholding at the middle of the record length. The results of the spatial and temporal analysis revealed that severe to extreme meteorological droughts were not generally a characteristic of the basin except the north and northeast parts.