Quality assurance of spectral ultraviolet measurements in Europe through the development of a transportable unit (QASUME)

Bais, A. F.; Blumthaler, M.; Gröbner, Julian; Seckmeyer, Günther; Webb, Ann R.; Görts, P.C.; Koskela, Tapani; Rembges, Diana; Kazadzis, Stelios; Schreder, Josef; Cotton, Peter B.; Kelly, P. J.; Kouremeti, Natalia; Rikkonen, Kimo; Studemund, H.; Tax, Rick; Wuttke, Sigrid

doi:10.1117/12.468641

Cited by 14 publications

(15 citation statements)

References 3 publications

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“…During the international intercomparison at Tylösand in 2000, about 10 spectroradiometers [ Thorseth et al , 2002], 10 radiometers and 3 multichannel radiometers (A. Dahlback et al, Intercomparison of 5 multi‐channel filter radiometers: Measurements of UV‐doses, total ozone abundances and cloud effects, submitted to The Nordic Intercomparison of Ultraviolet and Total Ozone Instruments at Tylösand, Sweden, in 2000 , final report, Finnish Meteorological Institute, Helsinki, 2004, hereinafter referred to as Dahlback et al, submitted manuscript, 2004) participated in the comparison. The Bentham spectroradiometer of the European Union project called “Quality Assurance of Spectral Ultraviolet Measurements in Europe” (QASUME) also made measurements during the solar comparison at Jokioinen, Finland in 2002 [ Bais et al , 2003]. In addition to these comparisons, the traveling reference was returned to the manufacturer in Norway for calibration in 2001 and 2002.…”

Section: Methodsmentioning

confidence: 99%

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Quality assurance of the solar UV network in the Antarctic

et al. 2005

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[1] Measuring ultraviolet radiation in the Antarctic region, where weather conditions are extremely challenging, is a demanding task. Proper quality control of the measurements and quality assurance of the data, which are the basis of all scientific use of data, has to be especially well planned and executed. In this paper we show the importance of proper quality assurance and describe the methods used to successfully operate the NILU-UV multichannel radiometers of the Antarctic network stations at Ushuaia, 54°S, and Marambio, 64°S. According to our experience, even though multichannel instruments are supposed to be rather stable as a function of time, severe drifts can occur in the sensitivity of the channels under these harsh conditions. During 2000-2003 the biggest drifts were 35%, both at Ushuaia and Marambio, with the sensitivity of the channels dropping at different rates. Without proper corrections in the data, this would have seriously affected the calculated UV dose rates. As part of the quality assurance of the network a traveling reference NILU-UV, which was found to be stable, was used to transfer the desired irradiance scale to the site NILU-UV data. Relative lamp tests were used to monitor the stability of the instruments. Each site NILU-UV was scaled channel by channel to the traveling reference by performing solar comparisons. The method of scaling each channel separately was found to be successful, even though the differences between the raw data of the site NILU-UV and the reference instruments were, before the data correction, as much as 40%. After the correction, the mean ratios of erythemally weighted UV dose rates measured during the solar comparisons in 2000-2003 between the reference NILU-UV and the site NILU-UV were 1.007 ± 0.011 and 1.012 ± 0.012 for Ushuaia and Marambio, respectively, when the solar zenith angle varied up to 80°. These results make possible the scientific use of NILU-UV data measured simultaneously at quite different locations, e.g., the Antarctic and Arctic, and the method presented is also practicable for other multichannel radiometer networks.

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Section: Methodsmentioning

confidence: 99%

“…During the international intercomparison at Tylösand in 2000, about 10 spectroradiometers [Thorseth et al, 2002], 10 radiometers and 3 multichannel radiometers (A. Dahlback [Bais et al, 2003]. In addition to these comparisons, the traveling reference was returned to the manufacturer in Norway for calibration in 2001 and 2002.…”

Section: Quality Assurancementioning

confidence: 99%

Quality assurance of the solar UV network in the Antarctic

et al. 2005

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“…Brewer #037 and Brewer #107 have both been frequently compared with the portable EU reference spectroradiometer QASUME, Quality Assurance of Spectral Ultraviolet Measurements in Europe (Bais et al, 2003). The comparisons provide external and additional evidence of the calibration stability of the instruments.…”

Section: Discussionmentioning

confidence: 99%

“…The Brewer spectrophotometer (Brewer, 1973;Bais et al, 1996) is a widely used instrument to monitor solar UV radiation. The instrument is used to collect photons of the incoming radiation through the entrance optics, separate the incoming photons according to their wavelength by a monochromator, and record the amount of photons at each wavelength.…”

Section: Introductionmentioning

confidence: 99%

In search of traceability: two decades of calibrated Brewer UV measurements in Sodankylä and Jokioinen

Heikkilä

Mäkelä

Lakkala

et al. 2016

Geosci. Instrum. Method. Data Syst.

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Abstract. The two Brewer spectrophotometers of the Finnish Meteorological Institute at Jokioinen and Sodankylä have been operated according to the highest levels of the WMO/GAW (World Meteorological Organization/Global Atmosphere Watch) recommendations with rigorous quality control and quality assurance. The calibration of the instruments is based on annual recalibrations of primary standard lamps in the VTT MIKES Metrology National Standards Laboratory in Finland and an exhaustive measurement program with measurements of standard and working lamps in the on-site optical laboratories. Over the years, the maintenance of the calibration has produced data sets of approximately 2000 lamp scans for both instruments. An extensive re-examination of the lamp measurements and the response of the spectrophotometers was carried out. The primary standard lamps were found to age on an average rate of 0.3 % per burn. The responsivity at wavelength 311 nm was found to exhibit both long-term and short-term changes. The overall long-term change was declining. In addition, abrupt changes of as large as 25 % were detected. The short-term changes were found to fluctuate on time frames shorter than the interval between the measurements of the primary standard lamps. This underlines the importance of the use of more frequently measured working standard lamps.

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“…6 Quality assessment Following Webb et al (2003), the quality assessment of an instrument can be done by comparing the instrument to other independent instruments measuring the same quantities. In this section, we review the results of intercomparison campaigns and comparison with the portable reference spectroradiometer QASUME (Quality Assurance of Spectral Ultraviolet Measurements in Europe) (Bais et al, 2003). For quality assurance purposes the measurements are also compared with reconstructed UV dose rates.…”

Section: Wavelength Alignmentmentioning

confidence: 99%

Quality assurance of the Brewer spectral UV measurements in Finland

et al. 2008

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Abstract. The quality assurance of the two Brewer spectrophotometers of the Finnish Meteorological Institute is discussed in this paper. The complete data processing chain from raw signal to high quality spectra is presented. The quality assurance includes daily maintenance, laboratory characterizations, calculation of long-term spectral responsivity, data processing and quality assessment. The cosine correction of the measurements is based on a new method, and is included in the data processing software. The results showed that the actual cosine correction factor of the two Finnish Brewers can vary between 1.08-1.13 and 1.08-1.12, respectively, depending on the sky radiance distribution and wavelength. The temperature characterization showed a linear temperature dependence between the instruments' internal temperature and the photon counts per cycle, and a temperature correction was used for correcting the measurements. The long-term spectral responsivity was calculated using the time series of several lamps using two slightly different methods. The long-term spectral responsivity was scaled to the irradiance scale of the Helsinki University of Technology (HUT) for the whole of the measurement time -periods 1990-2006 and 1995-2006 for Sodankylä and Jokioinen, respectively. Both Brewers have participated in many international spectroradiometer comparisons, and have shown good stability. The differences between the Brewers and the portable reference spectroradiometer QASUME have been within 5% during

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Quality assurance of spectral ultraviolet measurements in Europe through the development of a transportable unit (QASUME)

Cited by 14 publications

References 3 publications

Quality assurance of the solar UV network in the Antarctic

Quality assurance of the solar UV network in the Antarctic

In search of traceability: two decades of calibrated Brewer UV measurements in Sodankylä and Jokioinen

Quality assurance of the Brewer spectral UV measurements in Finland

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