A Comprehensive Assessment of Meteorological and Hydrological Drought Under Climate Change over the Upper Baro Watershed

Drought is a complex natural hazard resulting from meteorological and hydrological phenomena. Meteorological drought, defined by precipitation shortfalls, frequently precedes hydrological drought, decreasing surface and groundwater availability. The Upper Baro Watershed, an important agricultural and hydrological hub in Ethiopia, is becoming more vulnerable to climate change-induced droughts. This article investigates the comprehensive assessment of the meteorological and hydrological drought, focusing on their roles in the hydrological cycle, the transition from meteorological to hydrological drought, and the consequences for water resources management. The Standardized Precipitation Index (SPI) and the Stream Drought Index (SDI) are used to perform a thorough evaluation of the hydrological and meteorological drought characteristics of historical and projected future drought in the upper Baro watershed. Historical model data from 1985 to 2014, along with estimates under the SSP2-4.5 and SSP5-8.5 emission scenarios for the middle of the century (2041-2070) and end of the century (2071-2000). The association between the SPI and SDI indices was studied over 30 years across the basin. Overlapping periods of 3, 6, 9, and 12 months were discovered. This study analyzes the top four climate models, including MPI-ESM1-2-HR, FGOLAS-g3, GFDL-ESM4, and INM-CM4-8. These models are assessed based on the upper Baro watershed. The findings reveal that in the study area, the MPI-ESM1-2-HR and INM-CM4-8 models are the best-performing climate models for the upper Baro watershed under the future climate scenarios SSP2-4.5 and SSP5-8. The comprehensive assessment of the meteorological and hydrological drought under SSP2-4.5 and SSP5-8.5 climate scenarios. The findings show that in mid-century (2041-2071), under the SSP2-4.5 and SSP5-8.5 emission scenarios, moderately wet to severely dry conditions will occur. Additionally, by the end of the century (2071-2100), under the SSP2-4.5 and SSP5-8.5 emission scenarios, moderately dry to severe drought conditions will emerge over the upper Baro watershed. The findings suggest that both the SPI and SDI indices are capable of catching major droughts in the upper Baro watershed over the last 30 years. The study recommended that understanding this link is crucial for successful drought monitoring, forecasting, and mitigation efforts.