Unraveling solar irradiance dynamics in arid atmospheres: A multi-decadal wavelet coherence and probability density functions analysis with implications for air quality, climate, and renewable energy

Solar irradiance (SI) is a critical driver of atmospheric processes, with significant implications for air quality, climate change, and renewable energy potential. This study provides the first comprehensive assessment of decadal SI variability and trends across six major Saudi Arabian cities from 1984–2022, utilizing advanced statistical techniques including probability density functions, Mann–Kendall tests, and wavelet coherence analysis. Results reveal significant spatiotemporal variability in SI trends. Mean annual SI increased in five cities, with the highest rise in Buraydah (5.20 to 6.10 kW/m²/day) and decrease only in Dammam (5.35 to 5.24 kW/m²/day) from 1984–1993 to 2014–2022. Monthly probability density function analysis showed reduced SI variability and right-shifted distributions in recent decades for most cities. Mann–Kendall tests indicated increasing SI trends in Jeddah, Madinah, and Tabuk in the last decade, with declining trends elsewhere. Wavelet analysis revealed complex temporal patterns, with initial increases followed by recent declines in most cities. The average SI of 6.18 kW/m²/day across cities translates to a potential solar energy production of 406 kWh/year/m² at 18% efficiency. This study provides crucial insights for regional air quality modeling, climate change assessment, and renewable energy planning in arid regions, supporting Saudi Arabia's transition towards sustainable energy sources and improved environmental management.