1Dept. of Signal Theory and Communications, Remote Sensing Lab., Universitat Politècnica de Catalunya, Barcelona, Spain
2Institut d'Estudis Espacials de Catalunya, Universitat Politècnica de Catalunya, \newline Barcelona, Spain
3Andalusian Centre for Environmental Research, Junta de Andalucía, University of Granada, Granada, Spain
4Applied Physics Department, University of Granada, Granada, Spain
5Centro de Geofísica de Évora, Évora, Portugal
6Centro de Investigaciones Energéticas Medioambientales y Tecnológicas, Madrid, Spain
*now at: Centro de Geofísica de Évora, Évora, Portugal
Abstract. Lidar and sun-photometer measurements were performed intensively over the Iberian Peninsula (IP) during the eruption of Eyjafjallajökull volcano (Iceland) in April–May 2010. The volcanic plume hit all the IP stations for the first time on 5 May 2010. A thorough study of the event is conducted for the period 5–8 May. Firstly the spatial and temporal evolution of the plume is described by means of lidar and sun-photometer measurements supported with backtrajectories. The volcanic aerosol layers observed over the IP were rather thin (<1000 m) with a top height up to 11–12 km. The mean optical thicknesses associated to those layers were rather low (between 0.013 and 0.020 over the whole period). Punctually on 7 May the optical thickness reached peak values near 0.10. Secondly the volcanic aerosols are characterized in terms of extinction and backscatter coefficients, lidar ratios, Ångström exponents and linear particle depolarization ratio. Lidar ratios at different sites varied between 30 and 50 sr without a marked spectral dependency. Similar extinction-related Ångström exponents varying between 0.6 and 0.8 were observed at different sites. The temporal evolution of the backscatter-related Ångström exponents points out a possible decrease of the volcanic particle size as the plume moves from west to east. Particle depolarization ratios on the order of 0.06–0.08 confirmed the coexistence of both ash and non-ash particles. Additionally profiles of mass concentration were obtained with a method using the opposite depolarizing effects of ash particles (strongly depolarizing) and non-ash particles (very weakly depolarizing), and sun-photometer observations. In Granada the ash mass concentration was found approximately 1.5 higher than that of non-ash particles, and probably did not exceed the value of 200 μg m−3 during the whole event.