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Sensitivity of UV Erythemal Radiation to Total Ozone Changes under Different Sky Conditions: Results for Granada, Spain
Author(s) -
Antón Manuel,
Cazorla Alberto,
Mateos David,
Costa Maria J.,
Olmo Francisco J.,
AladosArboledas Lucas
Publication year - 2015
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12539
Subject(s) - overcast , cloud cover , sky , ozone , environmental science , atmospheric sciences , radiation , sensitivity (control systems) , meteorology , chemistry , physics , cloud computing , optics , electronic engineering , computer science , engineering , operating system
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.