Total ozone and solar erythemal irradiance in southwestern Spain: Day-to-day variability and extreme episodes

Abstract

This paper focuses on the influence of short-term chIges in total ozone column (TOC) on the variability of ultraviolet erythemal irradiance (UVER) at Badajoz (southwestern Spain). The study is performed on clear sky cases when the contribution of cloudiness and aerosols can be neglected. The period of study extends from 2001 to 2005. The results show that a reduction of 5% in TOC between two consecutive days may cause an increase of about 10% in UVER. The UVER variability associated to day-to-day changes in TOC presents a clear seasonal cycle with minimum values in summer and maximum in winter. Considering the monthly mean TOC value plus/minus two standard deviation as thresholds for identifying extreme events, the number of episodes with extreme low and high ozone amount was 54 and 9, respectively. The low ozone events occurred mainly in winter, causing a maximum increase of 30% in UVER. Copyright 2008 by the American Geophysical Union.