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CR prepress abstract   -  DOI: https://doi.org/10.3354/cr01696

Analysis of rainfall and temperature trends and variability in semi-arid Tharaka South Subcounty, Kenya

Caxton Gitonga Kaua*, Thuita Thenya, Jane Mutheu Mutune

*Corresponding author:

ABSTRACT: The impacts of climate variability, the spatiotemporal variations in the mean state of rainfall, temperature, and other climatic elements makes the analysis of the dynamics of climatic elements is imperative. Therefore, this study analyzed rainfall and temperature trends and variability in Tharaka South Subcounty, Kenya, using gridded rainfall and temperature data sourced from CHIRPS and CHIRTS. Variability analysis employed descriptive statistics, coefficient of variation, standardized anomaly, and precipitation concentration index. Trend analysis was done using Mann-Kendall (Z) statistical test and Sen’s slope (Q) estimator. The study area is marked by low rainfall with a decreasing trend. Local rainfall is generally marked by high and increasing variability, high and increasing concentration, and a high probability of extreme events. The study area experiences increasingly severe and frequent droughts with most of the years having below-average rainfall. Rainfall variability is thus associated with a decrease in rainfall, high rainfall concentration, extreme rainfall events, and more frequent and severe droughts. Large-scale climate forcings also influence the local rainfall trends and variability. In addition, the study area has high temperature levels that have an increasing trend, and the region is marked by a fluctuating temperature regime. An increase in temperature is associated with a reduction in rainfall amount. Moreover, the area is marked by spatial variability of rainfall and temperature that have positive and negative spatial trends. The findings of this study will improve understanding of climatic trends and variability, leading to a better understanding of their impacts and informing the development of effective response strategies.