Proposal of a new erythemal UV radiation amplification factor

Abstract. This work is aimed to propose a natural expansion of radiation amplification factor (RAF) for erythemal irradiance to consider all solar zenith angles cases together. In this direction, the article analyzes the relationship between measurements of UV erythemal radiation (UVER) recorded at Badajoz (Spain) and the total ozone column estimated by the instrument TOMS/NASA for that location during the period February 2001–December 2005. The new RAF parameter is formulated by power equation using slant ozone and UVER atmospheric transmissivity values. Thus, reliable values of this parameter have been reported. These values could serve as a new relevant index for comparison with other studies and model's result.

The new RAF is calculated with measurements recorded during completely clear cases using clearness index values higher than 0.75. The RAF value was 1.35±0.01, it is to say, when the slant ozone amount decreases 1% at Badajoz, UVER atmospheric transmissivity values and, therefore, UVER surface values approximately increase 1.35%. This result emphasizes the interest of measuring and monitoring simultaneous measurements of UV radiation and stratospheric ozone even for mid-latitudes. The influence of total ozone amount and cloudiness changes on new RAF values is analyzed. Cloud-free conditions allow to study the ozone influences while cloud effects are analyzed with all data by means of monthly average of slant ozone and UVER atmospheric transmissivities values.