A guide to measuring solar UV spectra using array spectroradiometers

Abstract

Array spectroradiometers are cost-effective instruments allowing fast measurement sequences to monitor the high variability of solar radiation. From the spectra any desired biologically weighted doses within their operational spectral range can be derived by post-processing. Therefore, array spectroradiometers have the potential to replace filter radiometers currently used in UV monitoring networks. However, they suffer significantly from stray light. Thus for routine operation it is important to follow strict procedures for characterisation, operation and data post-processing, which are suggested in these guidelines. The most important characteristics of array spectroradiometers are wavelength calibration, slit function, stray light properties, spectral structure of the dark signal, linearity, noise equivalent irradiance and spectral responsivity. For routine operation, temperature stabilization is absolutely necessary as well as automated dark signal measurements. Integration time and number of repetitions control the noise level and they have to be defined according to the measurement requirements. Data post-processing includes consideration of nonlinearity, dark signal with its spectral structure, integration time, stray light correction, spectral response function and weighting function. © 2013 AIP Publishing LLC.