Observed Changes in wet days and Dry Spells over IGAD region of Eastern Africa

Abstract Changes and variability in wet days and dry spells are crucial for Crop production and food security in Eastern Africa. This paper seeks to investigate the changes in wet days and dry spells over the Intergovernmental Authority on Development (IGAD) region. Data used are Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS). Several statistical methods, wet days and dry spells thresholds applied on decadal (10 years), 20, 30 and 41 time-scale. The results show the region exhibits decrease in the number of wet days and prolonged dry spells in the 1980s, while extra-ordinary increase in wet days was observed in recent decades (2011–2020). The majority of districts in Uganda, South Sudan, highlands of western Ethiopia and Kenya observed the highest number of wet days and lowest dry spells. These areas observed 90–100% probability of exceeding 7 and 14 consecutive wet days (1 and 2 spells) during March-May (MAM), June-September (JJAS) and October-December (OND). Arid and Semi-arid Lands (ASALs) in Kenya, Somalia, southeastern Ethiopia, Eritrea and Djibouti observed less than 5% of probability of exceeding 7, 14,21,28 days (1,2,3,4 spells). In addition, the floods events in 1997, 2018, 2019 and 2020, drought events in 1983, 1984, 1985 and 2021 over most parts of the region were driven by increase/decrease in number of wet days and dry spells. These findings are important for decision making, food security, planning adaptation and mitigation measures. Therefore, we recommend proper rain-fed agriculture planning, supplementary irrigation and Crop variety improvement in the IGAD region.