The Austrian radiation monitoring network ARAD – best practice and added value

Abstract

Abstract. The Austrian RADiation monitoring network (ARAD) has been established to advance the national climate monitoring and to support satellite retrieval, atmospheric modeling and the development of solar energy techniques. Measurements cover the downward solar and thermal infrared radiation using instruments according to Baseline Surface Radiation Network (BSRN) standards. A unique feature of ARAD is its vertical dimension of five stations, covering an altitude range between about 200 m a.s.l (Vienna) and 3100 m a.s.l. (BSRN site Sonnblick). The paper outlines the aims and scopes of ARAD, its measurement and calibration standards, methods, strategies and station locations. ARAD network operation uses innovative data processing for quality assurance and quality control, utilizing manual and automated control algorithms. A combined uncertainty estimate for the broadband shortwave radiation fluxes at all five ARAD stations, using the methodology specified by the Guide to the Expression of Uncertainty in Measurement indicates that relative accuracies range from 1.5 to 2.9 % for large signals (global, direct: 1000 W m −2 , diffuse: 500 W m −2 ) and from 1.7 to 23 % (or 0.9 to 11.5 W m −2 ) for small signals (50 W m −2 ) (expanded uncertainties corresponding to the 95 % confidence level). If the directional response error of the pyranometers and the temperature response of the instruments and the data acquisition system (DAQ) are corrected, this expanded uncertainty reduces to 1.4 to 2.8 % for large signals and to 1.7 to 5.2 % (or 0.9-2.6 W m −2 ) for small signals. Thus, for large signals of global and diffuse radiation, BSRN target accuracies are met or nearly met (missed by less than 0.2 percentage points, pps) for 70 % of the ARAD measurements after this correction. For small signals of direct radiation, BSRN targets are achieved at two sites and nearly met (also missed by less than 0.2 pps) at the other sites. For small signals of global and diffuse radiation, targets are achieved at all stations. Additional accuracy gains can be achieved in the future through additional measurements, corrections and a further upgrade of the DAQ. However, to improve the accuracy of measurements of direct solar radiation, improved instrument accuracy is needed. ARAD could serve as a useful example for establishing state-of-the-art radiation monitoring at the national level with a multiple-purpose approach. Instrumentation, guidelines and tools (such as the data quality control) developed within ARAD are intended to increase monitoring capabilities of global radiation and thus designed to allow straightforward adoption in other regions, without high development costs.

Baseline Surface Radiation Network (BSRN): structure and data description (1992–2017)

“…A more thorough description of BSRN methods and quality control issues can be found in Lanconelli et al (2011) and Matsui et al (2012), where issues especially related to polar BSRN sites are elaborated on. Other interesting papers on the quality and possible biases of radiation measurements were published by Vuilleumier et al (2014), who analyze the uncertainty of broadband shortwave radiation monitoring; Olefs et al (2016), who expand on measurement and calibration standards within the Austrian radiation monitoring network; and Nyeki et al (2017), who discuss pyrgeometer sensitivity on atmospheric integrated water vapor content.…”

“…Validation of models (Wild, 2008;Müller Schmied et al, 2016) and satellite-based estimates of surface radiation (Pinker et al, 2005) remain the focus of users. However, the data have also been used for trend analyses (Long et al, 2009) and aerosol studies (Xia et al, 2007;Kim and Ramanathan, 2008).…”

Comparison of Bacterial and Fungal Composition and Their Chemical Interaction in Free Tropospheric Air and Snow Over an Entire Winter Season at Mount Sonnblick, Austria

“…Radiation data from Mt. Sonnblick used as input was obtained within the ARAD network (Olefs et al, 2016). Snow height was obtained from an automatic TAWES laser snow gauge next to the snow pit sampling site, data validation was carried out using data from daily manual snow height measurements and via quality control algorithms.…”

An automated method for the evaluation of the pointing accuracy of Sun-tracking devices

“…In this paper, we present KSO-STREAMS, a platform-independent, fully automated, and cost-effective system to evaluate the pointing accuracy of Sun-tracking devices. During operation, KSO-STREAMS is mounted like a pyrheliometer on the Sun-tracking device to ensure correct imaging of the Sun's position, as identified by the tracking device To determine the pointing accuracy of the Sun-tracking device operated at the Kanzelhöhe Observatory Austrian radiation monitoring network (Olefs et al, 2016) site, observations by KSO-STREAMS, taken over a 15-week period from March to June 2015, were analyzed. Instrument performance was evaluated for valid KSO-STREAMS observations during four sets of ambient meteorological conditions: (i) nearly continuous clear sky, (ii) clear sky interrupted by frontal movement, (iii) variable cloud cover, and (iv) nearly perpetual overcast conditions.…”

“…Targets for instrument performance and operation are specified in the BSRN guidelines (McArthur, 2005). Furthermore, BSRN guidelines are (closely) adopted by national radiation monitoring networks, e.g., ARAD (Austrian radiation monitoring network) in Austria (Olefs et al, 2016), SACRaM in Switzerland (Wacker et al, 2011), or SURFRAD in the US (Augustine et al, 2005).…”