Monitoring of biologically effective UV irradiance at El Arenosillo (INTA), Andalucía, in Spain

Biological UV (ultraviolet) dosimetry was applied using the biofilm-technique (DLR patent) to determine the UV levels weighted of biologically weighted UV radiation at the INTA Sounding Station of El Arenosillo at Huelva, Spain (37° 06′N, 6° 44′W, 50 m.a.s.l.= above sea level) on 2 days in 1977 (April 1, and May 5). Exposure periods were calculated for clear sky days using a radiative transfer model for erythemal doses to reach 1.3 to 1.5 MED (minimal erythemal dose). Reliability of the radiative transfer model was demonstrated by the doses registered by a Yankee-UV biometer for the same exposure periods as used for the biosensor. This work presents the methodology employed (biofilm-technique utiliced, calculation of exposing periods with radiative transfer model, etc.) and the results obtained with the Yankee biometer and the biofilm. At noon, the ratio of biofilm measurements (Ieff, W/m2 = biological effective irradiance in W/ m2) to the UV Biometer data (in MED/h) was 3 - 4.