Assessment of precipitation and temperature shifts in Hiiraan region of Somalia using a VAR model

The study analyzed the long-term variability of precipitation and temperature in the Hiiraan Region, Somalia, spanning 1981 to 2024, using a Vector Autoregression (VAR) model. Diagnostic climate indices and trend detection methods, including the Precipitation Concentration Index (PCI), Seasonality Index (SI), Seasonal Standardized Anomaly Index (SAI), and the Mann–Kendall test with Sen’s slope estimator, were applied to characterize hydro-climatic changes. The results reveal a shift toward a more volatile climate regime. A dominant and increasing trend of strongly irregular rainfall was observed, with 16 years during 1981–2000 and 23 years during 2001–2024 falling within the strongly irregular category (PCI > 20). The Seasonality Index indicates increasingly concentrated and extreme rainfall patterns after 2000, while SAI analysis confirms persistent warming across seasons, more pronounced for minimum temperatures. The VAR (3) model captures dynamic feedback between rainfall and temperature, revealing asymmetric interactions and persistent warming responses. Mann–Kendall analysis shows statistically significant increasing trends in maximum temperature (p = 0.001) and minimum temperature (p < 0.001), while rainfall exhibits a non-significant trend (p > 0.05). PCI and SI display significant increasing trends (p < 0.05), indicating intensifying rainfall concentration over time. The findings underpin a transition toward a hydro-climatic regime characterized by intense rainfall pulses, increasing precipitation irregularity, and persistent warming trends, reinforcing the region’s exposure to compound climate extremes. Regional policy should prioritize strengthened flood management along the Shabelle River, improved water storage systems, and climate-resilient agricultural planning aligned with shorter, more concentrated rainy seasons.