Parameter Class A B Class C Class D Radiation screen with known Radiation High performance Well-maintained radiation screen Radiation screen with a characteristics and screen radiation screen with known characteristics and large influence of solar of known uncertainty over-estimation of Tx (daily max. of Tx < in 95% of radiation (for example, temperature) < in 95% of cases over-estimation of Tx in cases. when compared with a class A more than 5% of cases). radiation screen Air (achievable measurement > temperature uncertainty). Temperature Temperature probe with Temperature probe with Temperature probe and/or probe with uncertainty below uncertainty below (corresponds of acquisition system uncertainty < 0.4°C, with or equal (in laboratory class A of IEC 751 standard, Pt100 uncertainty lower than for good stability, such as Pt100. conditions, over the platinum probe). class C. Acquisition uncertainty < Uncertainty of the acquisition system measuring range). Or 0.2°C. Uncertainty of the < 0.1°C. Class D radiation screen. Class C radiation screen. acquisition system < . Class B radiation screen Or Temperature probe designed Class A radiation screen. Temperature probe/system Regular calibration against a to be calibrated and regular Yearly calibration in not designed to be traceable standard having an field verification (at least laboratory against a calibrated. uncertainty . ≤ traceable standard having an uncertainty . ≤ Redundant measurements can act as a continuous check on drift. Relative 3% (achievable 6% 10% > 10% humidity measurement uncertainty). Sensor specified for 6%, over a Sensor specified for 10%, Sensor with performances or Performance verified over temperature range typical for the over a temperature range specifications than the full range of humidity location of the station. typical for the location of the 10% over a temperature and a temperature range Acquisition uncertainty < 1%. station. range typical of the location B radiation screen typical for the location of the Acquisition uncertainty < of the station or acquisition station. Regular calibration against a 1%. uncertainty 1% Class C radiation screen. Acquisition uncertainty < or traceable standard having an 0.2%. Calibration not organized. uncertainty 2%. Regular calibration or field ≤ Class A radiation screen. Or verification (at least, 1 point Yearly calibration in Class D radiation screen. laboratory against a traceable standard having an uncertainty 1%. ≤
Parameter Class A B Class C Class D Radiation screen High performance radiation screen of known uncertainty Well-maintained radiation screen with known characteristics and over-estimation of Tx (daily max. temperature) < in 95% of cases when compared with a class A radiation screen Radiation screen with known characteristics and of Tx < in 95% of cases. Radiation screen with a large influence of solar radiation (for example, over-estimation of Tx in more than 5% of cases). Air temperature (achievable measurement uncertainty). Temperature probe with uncertainty below or equal (in laboratory conditions, over the measuring range). Uncertainty of the acquisition system < . Class A radiation screen. Yearly calibration in laboratory against a traceable standard having an uncertainty ≤ . Redundant measurements can act as a continuous check on drift. Temperature probe with uncertainty below (corresponds of class A of IEC 751 standard, Pt100 platinum probe). Uncertainty of the acquisition system < 0.1°C. Class B radiation screen Regular calibration against a traceable standard having an uncertainty ≤ . Temperature probe with uncertainty < 0.4°C, with good stability, such as Pt100. Acquisition uncertainty < 0.2°C. Class C radiation screen. Temperature probe designed to be calibrated and regular field verification (at least > Temperature probe and/or acquisition system uncertainty lower than for class C. Or Class D radiation screen. Or Temperature probe/system not designed to be calibrated. Relative humidity 3% (achievable measurement uncertainty). Performance verified over the full range of humidity and a temperature range typical for the location of the station. Acquisition uncertainty < 0.2%. Class A radiation screen. Yearly calibration in laboratory against a traceable standard having an uncertainty ≤ 1%. 6% Sensor specified for 6%, over a temperature range typical for the location of the station. Acquisition uncertainty < 1%. B radiation screen Regular calibration against a traceable standard having an uncertainty ≤ 2%. 10% Sensor specified for 10%, over a temperature range typical for the location of the station. Acquisition uncertainty < 1%. Class C radiation screen. Regular calibration or field verification (at least, 1 point > 10% Sensor with performances or specifications than 10% over a temperature range typical of the location of the station or acquisition uncertainty 1% or Calibration not organized. Or Class D radiation screen.
CIMO_A1-A2-Doc_4.3%20Sustaind%20performance%20Surface%20Classification_as_published.docx