Meteorological Drought in Northwestern Escarpment of Ethiopian Rift Valley: Detection Seasonal and Spatial Trends

Abstract

BackgroundThe Northwestern Escarpment of Ethiopian Rift Valley has been frequently affected by drought for decades in the major livelihood zones. This brought an adverse effect on the social and economic sectors because it affects significantly the smallholder farmers of the area. However, Most of these reviewed studies have limitations to show the evolutions, spatiotemporal drought frequencies, durations and severities in livelihood zone levels. Hence, the aim of this study was to monitor meteorological drought condition of the Alaje-Ofla (ALOF), Tserare Catchment (TC) and Raya Valley (RV) Livelihood Zones (LZ) from 1983 to 2016 using Standardized Precipitation Evapotranspiration Index (SPEI) at three months’ time scale. Both monthly Climate Hazards Group InfraRed Precipitations with Station data (CHIRPS) and Enhancing National Climate Service (ENACTS) temperature data (1983-2016) at moderate spatial resolution (i.e.,4 km-by-4km) were obtained from the National Meteorological Agency of Ethiopia. ResultsThis study uncovers seasonally recurring droughts that vary in severity, frequencies, and durations within as well as between the livelihood zones. The results indicated that severe drought occurred in all livelihoods zone of the study area from 1983/4 to 1991, while in the ALOFLZ and TCLZ relatively high droughts were observed. The severity and frequency of droughts were increased during the Belg (small rain) season, but decreased in Kiremt (summer) from the period 1989 to 2016. Hence, the severity of drought both on humans and livestock was severe in the area, particularly before the year 2001, but neither catastrophic drought nor food security in TCLZ and RVLZ was observed after year 2001.ConclusionStudying drought with long recorded meteorological data from a large number and uniformly distributed meteorological grids in small scale livelihood zones had great implications to identify the real trends of spatiotemporal meteorological drought. This enabled the researchers to investigate the real drought frequencies, severity, and durations in small scale areas. This study can support to improve the existing drought monitoring system and to build resilience to drought at household level.