Data Quality Objectives DATA QUALITY OBJECTIVES (DQO) FOR SOLAR ULTRAVIOLET RADIATION MEASUREMENTS Part I: Scanning Spectral and Broadband Instruments Addendum to WMO/GAW Report No. 146 Quality Assurance in Monitoring Solar Ultraviolet Radiation: State of

SUSANA DIAZ; VITALI FIOLETOV; SERM JANJAI; TAKASHI KOIDE; RICHARD MCKENZIE; GUNTHER SECKMEYER; CRAIG SINCLAIR; ANN WEBB; LIISA JALKANEN

World Meteorological Organization (WMO)

Lugar: Ginebra; Año: 2011 p. 11

Solar ultraviolet (UV) radiation can be measured by several different classes of instrument and the data applied to a range of objectives. It is crucial to match the instrument employed to the intended objective, and to ensure that sufficient facilities are available to support the objective in terms of personnel and QA/QC requirements. The technical specifications of the different types of instruments for measuring solar UV radiation are detailed in the GAW series of publications ?Instruments to measure solar ultraviolet radiation? [WMO/GAW Reports 125 scanning spectral, 164 broadband, 190 multi-filter instruments, and 191 array spectroradiometers) [WMO, 2001; WMO, 2008; WMO, 2010a and WMO, 2010b]. The following Data Quality Objectives (DQOs) apply to scanning spectral and broadband instruments, these reports should be read in conjunction with the following DQOs. Multi-filter [WMO, 2010a] and array spectroradiometers will be covered in a future addendum. Quality control and quality assurance issues are covered in further two GAW publications (WMO/GAW Report 126 and 146) [WMO, 1998 and WMO, 2003]. As mentioned above, the four types of instruments available for solar UV measurements are scanning spectroradiometers, broadband and multifilter instruments and array spectroradiometers. Spectral instruments provide high resolution spectral data that should cover the range 290-325 nm as a minimum, and ideally the full solar UV region 290-400nm. The spectral bandwidth should be less than 1 nm full width at half maximum and tolerances on other aspects of instrument performance are detailed in [WMO, 2001]. Spectral instruments are the most costly, complex and demanding of those available, but provide the most versatile data. Note that here, and in [WMO, 2001] we only refer to scanning-spectroradiometers and not to the solid state instruments that have recently become available (array spectroradiometers) [WMO, 2010b]. Broadband radiometers, for the purposes of this document, are taken as those instruments that measure the total erythemal (or ?sunburning?) irradiance (type B-1). These are the most common broadband UV instruments, although there are other designs that measure, for example, total UVA (315 ? 400 nm) radiation. A broadband erythemal radiometer has a response spectrum that approximates that of the erythema (sunburn) action spectrum [CIE, 1999]. Deviations between the actual meter response and the true erythemal action spectrum can be accounted for in the calibration process [WMO, 2008]. The UV index [WHO, WMO, UNEP and ICNIRP, 2002] is derived directly from the erythemal irradiance. The relative simplicity of broadband instruments means that they are cheaper to purchase and have fewer operational problems than scanning spectroradiometers. However, their maintenance and QA/QC can introduce substantial additional cost.