Temporal Variability of Sunshine Duration and Cloud Cover over Nigeria from 1970 to 2022

Abstract

This study investigates the temporal variability of sunshine duration and cloud cover across Nigeria from 1970 to 2022, leveraging satellite-based and ground-observed datasets to elucidate climatic trends and their implications for renewable energy, agriculture, and climate adaptation strategies. Using data from the Meteosat-based SARAH-2 climate data record, ERA5 reanalysis, and Nigerian Meteorological Agency (NIMET) ground stations, we analyze long-term trends, seasonal patterns, and spatial disparities in sunshine duration and cloud cover. Results indicate a significant increase in sunshine duration in northern Nigeria, averaging 0.5–0.7 hours per decade, driven by decreasing cloud cover, particularly during the dry season (November–March). Conversely, southern coastal regions exhibit higher cloud cover (up to 70% annually) and reduced sunshine duration due to monsoonal influences and orographic effects. Inter-annual variability is strongly correlated with the El Niño-Southern Oscillation (ENSO), with positive sunshine anomalies during El Niño years. Spatial analysis reveals pronounced disparities, with the semi-arid Sahel region experiencing the longest sunshine duration (8–9 hours/day) and the Niger Delta the shortest (4–5 hours/day). These trends align with global observations of decreasing cloud cover in tropical regions, potentially amplifying surface warming. The findings underscore the need for region-specific climate adaptation policies in Nigeria, particularly for solar energy optimization and agricultural planning. This study contributes to global climate research by providing a high-resolution analysis of a critical yet understudied region, with implications for sustainable development in sub-Saharan Africa.