Related Experiment Videos
Cloud cover and horizontal plane eye damaging solar UV exposures
1Centre for Astronomy, Solar Radiation and Climate, University of Southern Queensland, 4350 Toowoomba, Australia. parisi@usq.edu.au
International Journal of Biometeorology
|July 17, 2004
Summary
Cloud cover significantly impacts biologically damaging UV irradiance. This study quantifies UV effects on photokeratitis and cataracts, developing models for UV irradiance evaluation under various sky conditions.
Area of Science:
- Atmospheric Science
- Ophthalmology
- Photobiology
Background:
- Cloud cover is a major factor influencing UV radiation levels.
- Understanding UV irradiance's biological impact is crucial for health and safety.
Purpose of the Study:
- To investigate the effect of cloud cover on biologically damaging UV irradiances.
- To quantify UV effects on photokeratitis and cataracts.
- To develop models for evaluating UV irradiance under all sky conditions.
Main Methods:
- Spectral UV and cloud cover measured every 5 minutes over 6 months.
- Solar UV spectra recorded from 280-400 nm.
- Action spectra for photokeratitis and cataracts used for weighting UV irradiances.
Main Results:
- 85% of spectra showed a measured to cloud-free irradiance ratio of 0.6 or higher.
- 76% of spectra showed a ratio of 0.8 or higher.
- Empirical non-linear expressions relating UV irradiance to solar zenith angle were developed.
Conclusions:
- Cloud cover significantly reduces UV irradiance but does not eliminate biologically damaging levels.
- Developed models allow for the evaluation of UV irradiance for photokeratitis and cataracts under varying sky conditions.
- The findings contribute to a better understanding of UV exposure risks.