Meteorological Drought Magnitude, Duration, and Intensity in the Past and Future Climate of Eastern Tigray, Northern Ethiopia

Damasco Rubangakene , Gloria Peace Lamaro , Stephen Komakech, Atkilt Girma, Amanuel Zenebe

Drought assessment is a critical component of risk management in the comprehensive analysis of drought impacts. This study assessed the meteorological drought events under the past and future climate of Eastern Tigray, Northern Ethiopia, with the principal objective of enhancing early warnings and better drought disaster response mechanisms. To predict future climate, delta scenarios were created from 20 GCMs CMIP5 and Bias corrected Spatially Downscaled dataset. GCM ensembles were used to analyze the 4- and 12-month Standardized Precipitation Index (SPI) and Standardized Precipitation and Evapotranspiration Index (SPEI). The SPI and SPEI indices were computed using the two-parameter gamma probability (α, β) and log-logistic distributions (α, β and γ), respectively. The two indices revealed historical drought years 1982-83, 1984, 1985, 1999, 2002, 2003, 2004, 2005, 2008 and 2009. Based on the predicted climate data, SPI and SPEI indices revealed that Atsbi will likely experience a higher total magnitude of both short-term and long-term drought under the future climate. Considering short-term drought, the total number of consecutive dry months is expected to increase more in Fatsi based on both the SPEI-4 and SPI-4 timescale. Wukro, on the other hand, will experience the greatest increase in consecutive dry months in all-time segments and emission scenarios. Although the predicted climate showed increased precipitation in the future, it’s characteristically intermittent wet-dry cycles, coupled with higher evapotranspiration due to higher temperature. We recommend the adoption of climate-resilient rainwater harvesting and water conservation agriculture.