Applying the Penman-Monteith-FAO56 Model in the Estimation and Analysis of the Average Daily Solar Radiation During the Period 1985-2019 at Some Sites in Saudi Arabia

Abstract

The study provides an analysis of estimation of the average daily solar radiation, adopting six models, which are (Hargreaves-Samani, 1982), (Bristow-Campbell, 1997), (Samani, 2000), (Allen, 1995), (Chen et al., 2006) and (Annandale et al., 2002) using daily data of daily maximum, minimum and average temperatures ob-served during the period 1985-2019 (35 years) at nine climate stations affiliated to the National Center for Me-teorology, namely (Riyadh, Qaisumah, Abha, Buraydah, Tabuk, Al-Wajh, Arar, Tareef and Najran). The above statistical approaches were calibrated using the Penman-Monteith-FAO56 model as recommended by the food and agriculture organization of the united Nations,   the efficiency of these models' estimates was as-sessed using four statistical metrics: pBias, MAE, RSR, and RMSE.' The results of the study showed significant differences in the spatial distribution of solar radiation and the as-sociated temperatures, so that the differences P ranged between 5.2 and 8.4 MJ/m2/day for the Allen model, between 7.0 and 9.3 MJ/m2/day for the H-S model, between 10.6 and 20.5 MJ/ m2/day for the Samani model, and between 5.7 and 8.2 MJ/ m2/day for the Annandale model, and between 3.0 and 8.9 MJ/ m2/day for the BC model, and between 6.7 and 11.5 MJ/ m2/day for the Chen model. The results of the evaluation of the es-timation efficiency also showed that the best models are the Chen model at Abha, Qaisumah and Buraydah stations, the HS model at Al-Wajh and Najran stations, the Allen model at Riyadh and Arar stations, the An-nandale model at Tabuk station and the Samani model at Tarif station. It was also clear that the increasing temperature trends are not significant and do not have any statistical significance during the various months of the year at all the studied climatic stations.

Keywords

Temperature, solar radiation, statistical model, general trend of change, Saudi Arabia.

How to Cite

Al-Mulhim, A. (2025). Applying the Penman-Monteith-FAO56 Model in the Estimation and Analysis of the Average Daily Solar Radiation During the Period 1985-2019 at Some Sites in Saudi Arabia. Journal of Umm Al-Qura University for Social Sciences, Vol17(1), pp100-117. https://doi.org/10.54940/ss76369316

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