A very interesting paper has been just published in JGR (doi:10.1029/2011JD015836). My colleagues from the University of Valladolid (Julia Bilbao, Roberto Román, Argimiro de Miguel and David Mateos) have proposed a semiempirical method to obtain a long-term reconstructed series of ultraviolet erythemal irradiance (UVER) in Spain. For that, total shortwave radiation and total ozone columns measurements from satellite have been used.
The reconstructed hourly UVER irradiance values are in good agreement with the measurements in the seven locations, showing low RMSE values in summer (from 5% to 9%). A reconstructed 10 min UVER data set from 1991 to 2010 has been derived from the proposed method. Statistically significant UVER trends appear in summer and autumn when UVER levels increased 3.5% and 4.1% per decade, respectively.