Long-term spatial-temporal trends and variability of rainfall over Eastern and Southern Africa
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Date
2019
Journal Title
Journal ISSN
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Publisher
Springer
Abstract
This study investigates the spatial-temporal trends and variability of rainfall within East and South Africa (ESA)
region. The newly available Climate Hazards group Infrared Precipitation with Stations (CHIRPS-v2) gridded data
spanning 37 years (1981 to 2017) was validated against gauge observations (N = 4243) and utilised to map zones
experiencing significant monotonic rainfall trends. Standardised annual rainfall anomalies revealed the spatial-temporal
distribution of below and above normal rains that are associated with droughts and floods respectively. Results showed
that CHIRPS-v2 data had a satisfactory skill to estimate monthly rainfall with Kling-Gupta efficiency (KGE = 0.68 and
a high temporal agreement (r = 0.73) while also preserving total amount (β = 0.99) and variability (γ = 0.8). Two
contiguous zones with significant increase in annual rainfall (3–15 mm year−1
) occurred in Southwest Zambia and
in Northern Lake Victoria Basin between Kenya and Uganda. The most significant decrease in annual rainfall (−
20 mm year−1
) was recorded at Mount Kilimanjaro in Tanzania. Other significant decreases in annual rainfall ranging
between − 4 and − 10 mm year−1 were observed in Southwest Tanzania, Central-South Kenya, Central Uganda and
Western Rwanda. CHIRPS-v2 rainfall product provides reliable high spatial resolution information on amount of
rainfall that can complement sparse rain gauge network in rain-fed agricultural systems in ESA region. The observed
spatial-temporal trends and variability in rainfall are important basis for guiding targeting of appropriate adaptive
measures across multiple sectors.
Description
Journal Article
Keywords
spatial-temporal, rainfall, Africa