A comparative analysis of DEM-based models to estimate the solar radiation in mountainous terrain

• Published in: International journal of geographical information science : IJGIS Vol. 23; no. 8; pp. 1049 - 1076
• Main Authors: Ruiz-Arias, J. A., Tovar-Pescador, J., Pozo-Vázquez, D., Alsamamra, H.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 01-08-2009; Taylor & Francis LLC
• Subjects: Bias; Cartography; Comparative analysis; Complex topography; Digital elevation model; Errors; Geographic information systems; GIS; Irradiance; Solar energy; Solar radiation model; Ultraviolet radiation
• ISSN: 1365-8816; 1365-8824; 1362-3087
• DOI: 10.1080/13658810802022806

Daily solar radiation estimates of four up-to-date solar radiation models (Solar Analyst, r.sun, SRAD and Solei-32), based on a digital elevation model (DEM), have been evaluated and compared in a Mediterranean environment characterized by a complex topography. The models' estimates were evaluated against 40 days of radiometric data collected in 14 stations. Analyzed sky conditions ranged from completely overcast conditions to clear skies. Additionally, the role of the spatial resolution of the DEM has been evaluated through the use of two different resolutions: 20 and 100 m. Results showed that, under clear-sky conditions, the daily solar radiation variability in the study area may be reasonably estimated with mean bias errors under 10% and root mean square error values of around 15%. On the other hand, results proved that the reliability of the estimates substantially decreases under overcast conditions for some of the solar radiation models. Regarding the role of the DEM spatial resolution, results suggested that the reliability of the estimates for complex topography areas under clear-sky conditions improves using a higher spatial resolution.