Temporal Variation of Sunshine Duration and Its Potential Affecting Factors with Emphasis on Saudi Arabia for the Period 1983-2022

Abstract

The rising trend in fossil fuel prices and the depletion of natural resource reserves in the future force the authority of any country to find a more sustainable option for energy sources, so that future energy demand can be ensured for sustainable development. Assessing the trend and availability of sunshine duration (SD) at a spatiotemporal scale and the effect of different metrological parameters on the SD change is crucial to ensure the efficient utilization of solar energy, support the growth of renewable energy systems, and contribute to a sustainable future. In Saudi Arabia, The average monthly SD is 283 ± 18 hm-1, and there was a rising trend of SD that increased at a rate of 1.48 hy-1 with a 95% confidence level. Most of the regions experienced an annual mean of SD between 3375 and 3754 hy-1, except for the southwest and the middle-eastern part where SD was between 3072 and 3375 hours in a year.  The highest mean monthly SD was 318 ± 39 hm-1 during the summer season, but the trend of SD changes over the years was downward ( -0.21 hy-1). The mean monthly SD was lowest (244 ± 38 hm-1) in the winter season, and the changing pattern of SD was on the rise at a rate of 0.26 hy-1 with a 95% confidence level. There was a decline in SD across the country between 1983 and 1998, whereas from 2000 onward the country experienced an upward trend in SD. Relative humidity (R = -0.53, p < 0.01) and cloud cover (R = -0.42, p < 0.05) as potential factors have a strong negative correlation with SD, whereas wind speed (R = 0.06, p > 0.1) and temperature (R = 0.12, p > 0.1) have a positive correlation with SD in the region.