Solar Radiation Research Group coordinated by Professor José A. Martínez-Lozano focuses its activity on the study of atmospheric aerosols and solar radiation measurements. The group participates in the AErosol RObotic NETwork (AERONET) through the Iberian network for Sun photometer aerosol measurements (RIMA). Moreover, the Solar Radiation Research Group coordinates the European Skynet Radiometers network (ESR) in collaboration with the Institute of Atmospheric and Climate Sciences from the Italian National Research Council. ESR is a volunteer European observational network of Prede POM sun sky radiometers coordinated with SKYNET in Asia, and established and maintained by several universities and research institutes. The scientific objectives of both RIMA and ESR are the characterization of the atmospheric columnar aerosols and their interaction with clouds and solar radiation, and the validation of satellite products. The research group keeps two instrumented sites in Burjassot and Aras de los Olmos (Valencia, Spain) where columnar and in situ measurements of aerosols and solar radiation are conducted