Assessing the Relationship between GNSS-Derived Precipitable Water Vapour and Rainfall Trend in Nigeria

Abstract

Understanding the relationship between Precipitable Water Vapour (PWV) and rainfall intensity is essential for improving climate modeling, weather forecasting, and water resource management. This study explores the spatiotemporal and seasonal variability of PWV and its correlation with rainfall across Nigeria’s diverse climatic zones using GNSS-derived PWV and rainfall data from 2011 to 2016. A strong PWV–rainfall correlation is observed in the arid northern regions, especially in the Sudan/Sahel zone, where elevated atmospheric moisture content aligns with increased rainfall intensity. Conversely, in the Mangrove and Evergreen regions, high PWV levels do not consistently result in significant rainfall, implying the influence of additional meteorological factors such as convection dynamics and local circulations. Seasonally, the study reveals a delayed decrease in PWV during the post-monsoon period in coastal areas, indicating extended atmospheric moisture retention that supports lingering cloud cover and prolonged precipitation. In contrast, northern regions exhibit a rapid decline in PWV, marking a swift transition into dry conditions. Spatially, PWV varies between 0–85 mm in the Arid and Mangrove belts and 0–200 mm in the Wet and Dry Monsoon regions. These variations are shaped by proximity to moisture sources, topography, and prevailing wind systems. Rainfall distribution follows a clear coastal-to-inland gradient. The findings have critical implications for climate adaptation, agricultural planning, disaster risk reduction, and water resource sustainability. By deepening our understanding of atmospheric moisture dynamics, this study supports efforts to enhance food security, manage hydrological systems effectively, and strengthen climate resilience across Nigeria.