Satellite-based agro-meteorological drought assessment in North Eastern Ethiopia

Abstract

Drought has a profound and worsening socio-economic and environmental consequences in northeastern Ethiopia. This study assess agro-meteorological drought conditions in northeastern Ethiopia by integrating the Standardized Precipitation Index (SPI) and Vegetation Condition Index (VCI). The study employs CHIRPS satellite rainfall data and eMODIS NDVI imagery to analyze the spatiotemporal distribution of drought from 1981 to 2021. The Mann–Kendall (MK) test is used to evaluate trends in drought occurrences over the study period, while Pearson correlation analysis was conducted to examine the relationship between SPI and VCI during selected seasons and years. Results from SPI-3 indicate that severe drought events occurred in multiple years, with extreme drought conditions recorded in 1984 and 2015. The analysis highlights significant shifts in seasonal drought occurrences, with an observed trend of earlier onset of dry conditions in recent decades. VCI-based assessments corroborate SPI findings, revealing widespread severe to extreme drought conditions during key agricultural seasons, particularly in 2008, 2009, and 2013 for the Belg season and 2004 and 2015 for the Kiremit season. The MK trend analysis indicates a statistically significant increasing trend in precipitation during the Kiremit season (p < 0.05), suggesting a reduction in meteorological drought frequency, while the Belg season shows an increasing tendency toward drier conditions, though not statistically significant. The study identifies a shifting pattern in drought severity and timing, posing critical challenges to rain-fed agriculture and smallholder farmers’ food security. The findings underscore the need for enhanced drought monitoring systems and targeted policy interventions to mitigate drought impacts. The SPI-VCI integrated approach offers a comprehensive understanding of drought, supporting policymakers in building climate resilience in drought-prone regions.