Spatio-temporal analysis of rainfall variability and seasonality over Tekeze River Basin, Ethiopia

Abstract

This study examined the temporal patterns and spatial distribution of rainfall using Enhancing National Climate Services (ENACTS) time-series data from 1991 to 2020. The coefficient of variance (CV), precipitation concentration index (PCI), and standardized anomaly index (SAI) were employed to measure rainfall variability. The Mann–Kendall and Sen Slope estimator tests were used to analyze the rainfall trend. High rainfall variability occurred during the Bega (dry) season, whereas the Kiremt (wet) season experienced the highest annual rainfall in most rainfall grid locations. Geographically, the Tekeze River Basin experiences mean annual rainfall ranging from 600 to 1,600 mm over the study period. SAI also witnessed the presence of inter-annual variability of rainfall with negative and positive anomalies in 33.3% and 66.7% of the reference years, respectively. Assessing rainfall via scientific research to offer insights on rainfall distribution across various time scales is crucial for water resource managers and different sectors.