Study and Analysis of the Spatiotemporal Distribution of Global Solar Radiation in Libya Using NASA POWER Data and Geographic Information System (GIS) Techniques

Abstract

This study aimed to analyze the spatial and temporal distribution of global solar radiation in Libya, as well as to evaluate the accuracy of data derived from the NASA POWER platform by comparing it with ground-based measurements. The study relied on observed data from thirteen ground stations for the period (1984 - 1989), in addition to satellite-derived data represented by reanalysis data from the NASA POWER project for the period (1990–2024). Statistical indicators were employed to assess data accuracy, including RMSE, MAE, and R². The Kriging interpolation method was also used to perform spatial distribution analysis using ArcGIS. The results showed a strong correlation between ground measurements and NASA POWER data, as indicated by a coefficient of determination (R²) of 0.879, along with low estimation errors for both RMSE and MAE, which were 0.602 and 0.468 (kW.h/m²/day), respectively. Spatial distribution results, based on monthly, seasonal, and annual maps, revealed a clear gradient in global solar radiation from north to south, with higher values in southern and southeastern Libya, particularly in the regions of Jalu, Jaghbub, and Kufra. The southern and southeastern areas exhibited the highest radiation levels, while northern regions recorded the lowest. Specifically, summer was found to represent the peak season of solar radiation, followed by spring, autumn, and winter, with values ranging between 6.55–7.74, 4.67–7.35, 3.01–6.66, and 2.41-6.53 (kW.h/m²/day), respectively. The study also demonstrated that global solar radiation data obtained from the NASA POWER platform can be reliably used after proper validation. Furthermore, the study recommends strengthening ground monitoring networks and integrating them with remote sensing data to better support the optimal site selection for solar power plants in Libya.