Cloud observations for the statistical evaluation of the UV index at Toowoomba, Australia

• Published in: International journal of biometeorology 2008, Vol.52 (3), p.159-166
• Main Authors: Parisi, A. V, Sabburg, J, Turner, J, Dunn, P. K
• Format: Article
• Language: English
• Subjects: Algorithms; Animal Physiology; Atmosphere - analysis; Australia; Biological and Medical Physics; Biophysics; Clouds; Computer Simulation; Data Interpretation, Statistical; Earth and Environmental Science; Environment; Environmental Health; Environmental Monitoring - methods; Erythemal; Meteorology; Models, Statistical; Original Paper; Plant Physiology; Solar radiation; Spectrophotometry, Ultraviolet - methods; Statistical models; Ultraviolet radiation; Ultraviolet Rays; UV index; UVI; Weather
• ISSN: 0020-7128; 1432-1254
• DOI: 10.1007/s00484-007-0106-7

The development of a unique statistical model for the estimation of the UV index for all sky conditions with solar zenith angles of 60° or less is reported. The model was developed based on available data from an integrated whole-sky automated sky camera and UV spectral irradiance measurement system that was collected every 5 min when the equipment was operational over a period of 1 year. The final model does not include terms directly associated with solar radiation, but rather employs terms, and interactions between these terms, including the parameters of sky cover, solar obstruction, and cloud brightness. The correlation between the estimations of the model and the measured values was 0.81. The developed model was evaluated on a data set spanning 5 months that had not been employed in the development of the model. The correlation for this new data set was 0.50, which increased to 0.65 for the cases when the clouds were considered to be a contributor to UV enhancement above that of a cloud-free day.