Abstract:
Measurement of solar ultraviolet radiation (UVR) is important for the assessment of
potential beneficial and adverse impacts on the biosphere, plants, animals, and humans. Excess solar
UVR exposure in humans is associated with skin carcinogenesis and immunosuppression. Several
factors influence solar UVR at the Earth’s surface, such as latitude and cloud cover. Given the potential
risks from solar UVR there is a need to measure solar UVR at di erent locations using e ective
instrumentation. Various instruments are available to measure solar UVR, but some are expensive
and others are not portable, both restrictive variables for exposure assessments. Here, we compared
solar UVR sensors commercialized at low or moderate cost to assess their performance and quality of
measurements against a high-grade Bentham spectrometer. The inter-comparison campaign took
place between March 2018 and February 2019 at Saint-Denis, La Réunion. Instruments evaluated
included a Kipp&Zonen UVS-E-T radiometer, a Solar Light UV-Biometer, a SGLux UV-Cosine
radiometer, and a Davis radiometer. Cloud fraction was considered using a SkyCamVision all-sky
camera and the Tropospheric Ultraviolet Visible radiative transfer model was used to model clear-sky
conditions. Overall, there was good reliability between the instruments over time, except for the Davis
radiometer, which showed dependence on solar zenith angle. The Solar Light UV-Biometer and the
Kipp&Zonen radiometer gave satisfactory results, while the low-cost SGLux radiometer performed
better in clear sky conditions. Future studies should investigate temporal drift and stability over time.
