Abstract:
Climate change and variability is one of the current global environmental problem. Ethiopia is more
vulnerable to the problem of climate change due to its low adaptive capacity. In recent years, drought has been
occurring frequently in all climatic zones and significantly affecting crop yields causing shortage of food as
well as animal forage. In order to recommend possible adaptation options, assessing climate variability, and
agricultural drought condition is very vital. To this end, this study aimed to assess climate variability and
agricultural drought condition in East wollega zone.
Thirty years’ rainfall and temperature data, crop yield data, eMODIS NDVI, MOD11A2 Terra v.0005 LST,
CHIRP PPT Africa, were used. Mann Kendall trend test and Sen’s slop estimators were used to examine
rainfall and temperature trend. A simple linear regression model was applied to examine the relationship
between NDVI and rainfall as well as to validate satellite based VHI estimation based on crop yield data. The
satellite images were processed using ARC GIS 10.8 software.
The result of the study shows that, though the trend in temperature was increased, insignificant decreasing trend
has been observed in rainfall during the study period. Based on VHI and SPI analysis, the years 2009 and 2015
were considered as the drought years while 2006 and 2018 were taken as wet years. Though all districts of the
zone have experienced agricultural drought, its occurrence was more frequent in the southern and
southeastern parts of the area. Correlation analysis among various drought elements indicate the existence of
weak and positive relationship between VHI and crop yield but strong and positive correlation between
NDVI and rainfall in the area. Climate change early warning, irrigation agriculture and local level adaptations
are highly recommended to get rid of the effects of drought in the area. Moreover, VHI and SPI based
assessment of agricultural drought is recommended to be used by the decision makers for agricultural
drought monitoring and early warning system.
