Articles | Volume 12, issue 1
https://doi.org/10.5194/asr-12-147-2015
https://doi.org/10.5194/asr-12-147-2015
09 Jul 2015
 | 09 Jul 2015

UV and global irradiance measurements and analysis during the Marsaxlokk (Malta) campaign

J. Bilbao, R. Román, C. Yousif, D. Mateos, and A. de Miguel

Abstract. A solar radiation measurement campaign was performed in the south-eastern village of Marsaxlokk (35°50' N; 14°33' E; 10 m a.s.l), Malta, between 15 May and 15 October 2012. Erythemal solar radiation data (from a UVB-1 pyranometer), and total horizontal solar radiation (global and diffuse components) from two CM21 pyranometer were recorded. A comparison of atmospheric compounds from ground measurements and satellites shows that TOC (total ozone column) data from the Ozone Monitoring Instrument OMI, TOMS and DOAS algorithms correlate well with ground-based recorded data. The water vapour column and the aerosol optical depth at 550 nm show a significant correlation at the confidence level of 99 %. Parametric models for evaluating the solar UV erythemal (UVER), global (G) and diffuse (D) horizontal irradiances are calibrated, from which aerosol effects on solar irradiance are evaluated using the Aerosol Modification Factor (AMF). The AMFUVER values are lower than AMFG, indicating a greater aerosol effect on UVER than on global solar irradiance. In this campaign, several dust event trajectories are identified by means of the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model and by synoptic conditions for characterizing desert dust events. Hence, changes in the UV index due to atmospheric aerosols are described.

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Short summary
A solar radiation measurement campaign was performed in the south-eastern village of Marsaxlokk (35º 50' N; 14º 33' E; 10 m a.s.l.), Malta, between 15 May and 15 October 2012. Erythemal solar radiation (UVER), horizontal global and diffuse components were recorded. Aerosols effects on solar irradiances are evaluated using the Aerosol Modification factor (AMF). Results indicate a greater aerosol effect on UVER than on global solar irradiance. Several dust event trajectories are identified.