Abstract:
Rainfall variability is one of the most significant climate variables for global agricultural
productivity. It has also effect on the agricultural activities, water and food security over the
Wolaita Zone. Station and merged satellite data from 1990 to 2020 and also the two stages
of the Coupled Model Intercomparison Project (CMIP6) data to analyze historical (1985 to
2014) and future projected meteorological drought changes from (2041-2100) using two
Shared Socioeconomic Pathway (SSP) under SSP2-4.5 and SSP5-8.5 emission scenarios
were used in this study. The variability of rainfall at the annual, seasonal, and monthly
scales was analyzed by using the coefficient of variation (CV) and standardized rainfall
anomalies (SRA) over the study area. The modified Mann-Kendall test was used to
determine the upward or downward trend and Sen’s slope estimator was used to determine
increasing or decreasing in the magnitude. The correlation analysis was used to show the
linkage between sea surface temperatures (SST) with Belg and Kiremt rainfall in the
research area. In this study, the power transformation (PT) bias correction method was used
to correct the GCM (CMIP6) model data with the observed rainfall dataset serving as a
reference. The SPI is the drought index, which indicates historical and future projected
meteorological drought conditions at different severity levels that range from normal to
extreme drought conditions. The belg rainfall is much more variable than the Kiremt and
annual rainfall. During Belg season Indian Ocean Dipole (IOD) is positive or warming and
the central Pacific Ocean is warming or during the El Niño phase rainfall increases in
amount and distribution. During Kiremt season Indian Ocean Dipole (IOD) is positive or
warming and the central Pacific Ocean is cooling or during the La Niña phase rainfall
increases in amount and distribution. Future projected meteorological drought will be more
affected by extreme and severe drought during the middle and far future under SSP2-4.5
and SSP5-8.5 scenarios, which is more frequent and intense than historical time over the
study area. This study provides important guidance for identifying causes, minimizing
impacts, and enhancing resilience to droughts over the Wolaita Zone.
