Advances in traceability of solar ultraviolet radiation measurements
Year: 2002
Type: dissertation
Abstract: Measurements of solar ultraviolet radiation (UVR) at STUK commenced in 1989, five years after the alarming observation of the ozone depletion in the Antarctic and in association with the establishment of the solar UV monitoring network of the Finnish Meteorological Institute. It was soon realised that the instrumentation for solar UVR measurements was far from adequate for the challenging task of measuring the solar UV spectrum. In addition, the intercomparison of lamps used as secondary standards of UV irradiance between the National Standard Laboratories revealed significant discrepancies. In the course of this study, a national lamp-based scale for UV irradiance was established by STUK and subsequently was confirmed with the detector-based scale of the Helsinki University of Technology (HUT). Methods for (i) radiometric testing, (ii) calibration and (iii) data correction were developed for solar UV spectroradiometers and for broadband erythemally weighted (EW) solar UV radiometers. A common opinion in the early 1990s was that EW radiometers were not good enough for solar UV monitoring; spectroradiometers or multi-channel narrow band radiometers were seen as the only option for reliable solar UV radiometry. Later on, several intercomparisons revealed that, without stringent methods of quality control (QC) and quality assurance (QA), even high precision spectroradiometers easily yield UV data erroneous by 20% or more. The reliability of the spectroradiometric solar UVR measurements made by STUK was verified in the Nordic solar UV radiometer intercomparisons in 1993 and 1996 and in the largest European intercomparison of solar UV spectroradiometers in 1997. At STUK, it was considered that the low cost and easy-to-operate EW radiometers also had a role in solar UV monitoring. After developing the calibration methods for EW radiometers and gaining experience in testing of 16
Source: Työväentutkimus Vuosikirja
Author: Kirsti Leszczynski
Language: English
Subfield: Aerospace Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1968419841