Measurement variation and the factors influencing the UV index

Abstract

The article presents a technique to measure the ultraviolet index using a personal hand held ultraviolet meter to illustrate concepts of physics. Measurements of the erythemally effective (sun-burning) direct solar beam, diffuse skylight, and total global ultraviolet irradiance are converted to daily ultraviolet index measurements. Daily ultraviolet index measurements are then compared to the daily forecast ultraviolet index. The influence of the local environment on the measured and forecast ultraviolet index is further examined with respect to surface reflection, shade structures, trees and buildings placed within the local environment, which each play a significant role in influencing the ultraviolet index at any one location. The measurement techniques presented in the article are provided to suit primary and secondary school aged children.