As global warming increasingly affects vulnerable regions such as Central
East Africa, it is crucial to understand future changes in rainfall variability
to reduce vulnerability. Despite the importance of rainfall variability, it has
received less attention compared to changes in mean and extreme rainfall. This
study evaluates the amplification of synoptic (weekly) to annual variability of
East African Monsoon (EAM) Long Rainfall (March to May) by climatic extremes.
Using band-pass filtered daily rainfall data, we found that EAM rainfall
variability is anticipated to increase by 20% - 60% across the region under
global warming conditions. The majority of the intermodal variability in Long
Rain EAM rainfall forecasting is explained by differences in mean rainfall. Our
results show that the synoptic variability of Long Rain for EAM rainfall is
likely to amplify, resulting in more extreme rainfall events and longer dry
spells under global warming. This amplification is attributed to the warming of
the Indian Ocean and the associated changes in atmospheric circulation
patterns. The projected increase in synoptic to annual variability of Long Rain
for EAM rainfall has significant implications for water resources management
and agriculture in the region, challenging policymakers to develop adaptive
strategies that can mitigate the impacts of these extreme events. This study
emphasizes the potential impacts of projected climate changes in rainfall
variability on the East African region at all periods and underscores the need for effective adaptation strategies to ensure
sustainable development.
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