Assessing climate variability and trends in global solar radiation over Saudi Arabia using the CLARA-A3 dataset

Abstract

The spatio-temporal distribution of global solar radiation (GSR) is essential for the effective integration of photovoltaic (PV) energy systems. Therefore, this study aims to investigate the long-term trend, variation, fluctuation, and abrupt changes of the GSR over Kingdom of Saudi Arabia (KSA). The observed GSR data from World Radiation Data Center (WRDC) were used to evaluate the gridded 0.25° × 0.25° CLARA-A3 dataset at the available five stations. The GSR data at another 10 stations from the CLARA-A3 dataset covering the different climatic regions in KSA during the period from 1979 to 2023 were extracted to facilitate the analysis and interpretation of GSR. The results showed that, CLARA-A3 produced high accuracy and reliability GSR data over KSA. Also, the monthly GSR ranges from 140 to 240 W/m² as minimum during winter and from 280 to 340 W/m² as maximum during summer. The coefficient of variation (CV) gradient, both annual and seasonal, varies from around 0.5 %–6 %, with the highest gradient occurring in the mountainous regions in southwestern KSA. Furthermore, the GSR has a positive Mann-Kendall (MK) trend during spring, followed by winter and annual trends, whereas a negative MK trend is detected during summer. The climatological variability of annual GSR behavior, analyzed using Gaussian and binomial low-pass filters, indicates a positive trend at the majority of stations. Finally, the first positive abrupt change in GSR values at all stations is found in 1999 and 2001, while the negative abrupt change was detected in 1992 at only three stations.