Download site for solar radiation maps of the Iberian Peninsula, calculated using the CAC method
The solar radiation maps on this website are raster layers with a resolution of 100 m, in UTM-30N projection with the ETRS89 datum. They contain solar radiation data for the Iberian Peninsula and are available in two formats:
- MiraMon: .img in .mmzx (ISO 19165:2018), openable directly in MiraMon. - GeoTIFF: .tif in .zip (ISO/IEC 21320-1:2015), openable in various environments after downloading the ZIP.
The CAC (Constant Atmospheric Conditions) method is a calculation algorithm that provides an estimate of solar radiation on the land surface based on a standard and constant atmosphere (in this case with an atmospheric optical depth τ0=0.288, typical of clear days, and a contribution of diffuse radiation constant equal to 20 % of the direct radiation). The solar position relative to the center of the study area allows the calculation of solar vector incidence angles, considering the relief and topographic cast-shading by incorporating a Digital Elevation Model (DEM), as well as astronomical procedures, atmospheric extinction, and other factors. The calculations have been carried out taking into account the Sun's position every 30' from sunrise to sunset, using the InsolDia application within the free MiraMon GIS software, and the results are provided in energy units [kWh/(m²·day)].
CAC: Potential Solar Radiation (Dec 2004–2020)
As a comparative alternative to the CAC method, you can also download solar radiation data based on the InsolMets procedures, a method that provides a more accurate and realistic treatment of the atmosphere thanks to the use of remote sensing data and other input parameters.
The data on this website have been prepared by Catalina Roca-Fernández, Xavier Pons and Miquel Ninyerola, from the Grumets research group at the Universitat Autònoma de Barcelona, as part of a comparative study of methods for calculating solar radiation in the Iberian Peninsula, published in:
➠ Roca-Fernández, C.; Pons, X.; Ninyerola, M. (2025). "A Comparison of Different Solar Radiation Models in the Iberian Peninsula". Atmosphere, 16(5), 590. Doi: 10.3390/atmos16050590
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Additional related publications
⟹ DIGITAL ELEVATION MODEL AND SOLAR ILLUMINATION GEOMETRY
The DEM used to compute the CAC model is available at:
https://www.infoambiental.grumets.cat/RadSolarPI/DEM/DEM_Iberian_Peninsula_100m.mmzx (.img in .mmzx)
https://www.infoambiental.grumets.cat/RadSolarPI/DEM/DEM_Iberian_Peninsula_100m.zip (.tif in .zip)
The DEM tessellation used for calculating the solar illumination geometry is available at:
https://www.infoambiental.grumets.cat/RadSolarPI/DEM/DEM_Tessellation_WithOverlap.zip (.xlsx in .zip; NOTE: Excel file with two sheets {Y and X coordinates})
https://www.infoambiental.grumets.cat/RadSolarPI/DEM/DEM_Tessellation_WithoutOverlap.zip (.xlsx in .zip; NOTE: Excel file with two sheets {Y and X coordinates})
The DEM methodology and the procedure for calculating the solar illumination geometry have been published in:
➠ Roca-Fernández, C.; Ninyerola, M.; Pons, X. (2022). "Mejoras en el cálculo de los Modelos Digitales de Radiación Solar a partir del tratamiento del MDE y de la incorporación del patrón espaciotemporal de la profundidad óptica atmosférica: Resultados preliminares para la Península Ibérica". XIX Congreso de Tecnologías de la Información Geográfica – Las TIG al Servicio de los ODS (Departamento de Geografía y Ordenación del Territorio de la Universidad de Zaragoza, y la Asociación de Geógrafos Españoles), pp. 391-400, 12-14 September 2022, Zaragoza (Spain). Doi: 10.26754/uz.978-84-18321-49-8. ResearchGate: Conference Paper
⟹ SOLAR RADIATION NETWORKS
The solar radiation networks used to validate the CAC model are available at:
Solar radiation network AEMET-Spain
Solar radiation network SNIRH-Portugal
- The meteorological stations from the AEMET-Spain network are available at:
https://www.infoambiental.grumets.cat/RadSolarPI/Networks/SolarRadNet_AEMET_Spain.zip (.csv in .zip)
https://www.infoambiental.grumets.cat/RadSolarPI/Networks/SolarRadNet_AEMET_Spain_ETRS89.mmzx (.pnt in .mmzx)
https://www.infoambiental.grumets.cat/RadSolarPI/Networks/SolarRadNet_AEMET_Spain_WGS84.mmzx (.pnt in .mmzx)
* To request solar radiation data from the AEMET-Spain network, please contact: Services AEMET-Spain
- The meteorological stations from the SNIRH-Portugal network are available at:
https://www.infoambiental.grumets.cat/RadSolarPI/Networks/SolarRadNet_SNIRH_Portugal.zip (.csv in .zip)
https://www.infoambiental.grumets.cat/RadSolarPI/Networks/SolarRadNet_SNIRH_Portugal_ETRS89.mmzx (.pnt in .mmzx)
https://www.infoambiental.grumets.cat/RadSolarPI/Networks/SolarRadNet_SNIRH_Portugal_WGS84.mmzx (.pnt in .mmzx)
* The solar radiation data from the SNIRH-Portugal network is available at: https://www.infoambiental.grumets.cat/RadSolarPI/Networks/SolarRadData_SNIRH_Portugal_2001_2020.zip (.csv in .zip)
- The meteorological stations from the AEMET-SNIRH network across the Iberian Peninsula are available at:
https://www.infoambiental.grumets.cat/RadSolarPI/Networks/SolarRadNet_AEMET_SNIRH_Iberia.zip (.csv in .zip)
https://www.infoambiental.grumets.cat/RadSolarPI/Networks/SolarRadNet_AEMET_SNIRH_Iberia_ETRS89.mmzx (.pnt in .mmzx)
https://www.infoambiental.grumets.cat/RadSolarPI/Networks/SolarRadNet_AEMET_SNIRH_Iberia_WGS84.mmzx (.pnt in .mmzx)
The methodology for integrating the two Iberian solar radiation networks has been published in:
➠ Roca-Fernández, C.; Ninyerola, M.; Pons, X. (2024). "Diagnosis for integrating the main Iberian networks of solar radiation meteorological stations". GeoFocus, 33, pp. 43-75. Doi: 10.21138/GF.850
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CAC model solar radiation layers are available in different formats
- Monthly climate data: 12 layers (one per month), providing average values for that month over the entire 2004–2020 period.
- Monthly data for each year: These results of the CAC model are not listed, as they match the monthly climate data (2004–2020). This is because the CAC model was developed using a simplified solar illumination geometry, constant atmospheric conditions, and without considering cloud cover fraction conditions. These characteristics limit the model's temporal variability (only minor astronomic differences between years exist), which is why its results are virtually identical to the monthly averages provided.
- Global data: 1 layer for the entire period, providing both average and median values (2004–2020).
➢ Monthly climate data (2004–2020):
➢ Global data (2004–2020):
For any questions you can write to Xavier.Pons@uab.cat