title: Sensitivity of UV Erythemal Radiation to Total Ozone Changes under Different Sky Conditions: Results for Granada, Spain.
abstract: This study focuses on the analysis of the sensitivity of UV erythemal radiation (UVER) to variations in the total ozone column (TOC) under different sky conditions at Granada (southeastern Spain). The sensitivity is studied both in relative terms by means of the Radiation Amplification Factor (RAF) and in absolute terms using the Ozone Efficiency (OE). These two variables are determined for diverse sky conditions characterized by the cloud cover information given by a sky camera (in oktas) and the cloud optical depth (COD) estimated from global solar radiation measurements. As expected, in absolute terms, the TOC variations cause substantially smaller UVER changes during completely overcast situations than during cloud-free cases. For instance, the OE (SZA = 30°, TOC = 290 DU) decreases from 0.68 mW m(-2) per unit of TOC (0 oktas) to 0.50 mW m(-2) per unit of TOC (8 oktas). However, the opposite is observed when the analysis is performed in relative terms. Thus, the RAF (determined for SZA cases below 80°) increases from 1.1 for cloud-free cases (0 oktas) to 1.4 for completely overcast situations (8 oktas). This opposite behavior is also found when both RAF and OE are analyzed as functions of COD. Thus, while the OE strongly decreases with increasing COD, the RAF increases as COD increases.
authors.affiliation: Departamento de Física, Universidad de Extremadura, Badajoz, Spain.|Departamento de Física, Instituto de Ciências da Terra, Escola de Ciências e Tecnologia, Universidade de Évora, Évora, Portugal.
authors.forename: Manuel
authors.initials: M
authors.lastname: Antón
authors.affiliation: Instituto Interuniversitario del Sistema Tierra en Andalucía, Granada, Spain.|Departamento de Física Aplicada, Universidad de Granada, Granada, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Cazorla
authors.affiliation: Grupo de Óptica Atmosférica (GOA), Universidad de Valladolid, Valladolid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Mateos
authors.affiliation: Departamento de Física, Instituto de Ciências da Terra, Escola de Ciências e Tecnologia, Universidade de Évora, Évora, Portugal.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Costa
authors.affiliation: Instituto Interuniversitario del Sistema Tierra en Andalucía, Granada, Spain.|Departamento de Física Aplicada, Universidad de Granada, Granada, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Olmo
authors.affiliation: Instituto Interuniversitario del Sistema Tierra en Andalucía, Granada, Spain.|Departamento de Física Aplicada, Universidad de Granada, Granada, Spain.
authors.forename: Lucas
authors.initials: L
authors.lastname: Alados-Arboledas