Ethiopia has been affected by several droughts over the last few decades, with the latest 2015 drought being the worst in half a century. Agriculture, being the predominant sector of the country’s economy, is rain-fed and is therefore most susceptible to droughts. Developing a reliable remotely sensed tool can help in reliable detection of drought. This project implemented a scaled drought index utilizing NASA’s Aqua/Terra Moderate Resolution Imaging Spectroradiometer (MODIS), Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) Integrated Multi-satellite Retrievals for GPM (IMERG) data to assess agricultural drought and its spatio-temporal characteristics at a regional scale over the last 10 years. The index maps and decision support tools were provided to the project partners to supply timely information for humanitarian aid, and to build their capacity to monitor droughts in the future.
Analysis of the time-series of mean annual drought index across the four climatic zones revealed that the spatial patterns of drought vary significantly with time. This is because the spatial drought patterns largely reflect the variation in seasonal precipitation due to Intertropical Convergence Zone (ITZC). We observed that the annual drought (for the meher season) was most prominent in NW Highlands and SW Rainforest in 2009, and in NE Highlands and Central Highlands in 2015. Both 2009 and 2015 droughts were associated with the occurrence of El-Nino events (NOAA, 2015), and 2011 and 2012 brought abnormally dry conditions in SW Rainforest, and Central and NE Highlands.