Thermal Sensors IR20 & IR20WS Research grade pyrgeometers IR20 is a research grade pyrgeometer suitable for high-accuracy longwave irradiance measurement in meteorological applications. Thanks to Hukseflux’ technological innovation, IR20 is offered at a significantly lower price level than competing models of the same performance level. IR20 is capable of measuring during both day and night. In absence of solar radiation, model IR20WS offers even better accuracy because of its wider spectral range. Figure 2 overview of IR20 pyrgeometer: (1) cable, (2) fixation of sun screen, (3) dome with solar blind filter, (4) sun screen, (5) humidity indicator, (6) desiccant holder, (7) levelling feet, (8) bubble level, (9) connector IR20 measures the longwave or far-infra-red radiation received by a plane surface, in W/m2, from a 180° field of view angle. In meteorological terms pyrgeometers are used to measure “downward and upward longwave irradiance” (WMO definition). Longwave radiation is the part of radiation that is not emitted by the sun. The spectral range of longwave radiation is not standardised. A practical cut-on is in the range of 4 to 5 x 10-6 m. IR20 has a dome with a solar blind filter with a cut-on at 4.5 x 10-6 m, making it suitable for day- and night observations. Model IR20WS has a wide spectral range with a cut-on at 1.0 x 10-6 m. It offers a superior accuracy during night-time, when solar radiation is absent. Copyright by Hukseflux. Version 1301. We reserve the right to change specifications without prior notice Page 1/2. For Hukseflux Thermal Sensors go to www.hukseflux.com or e-mail us: [email protected]

Thermal Sensors IR20 & IR20WS specifications Measurand Optional measurand Optional measurand Spectral range IR20 Spectral range IR20WS IR20WS restrictions for use Field of view angle Response time (95 %) Sensitivity (nominal) Rated operating temperature range Temperature dependence Calibration traceability Optional traceability Temperature sensor Heater Standard cable length longwave radiation sky temperature surface temperature 4.5* to 40 x 10-6 m 1.0 to 50 x 10-6 m only in the absence of solar radiation 180° 3s 17 x 10-6 V/(W/m2) -40 to +80 oC < ± 0.4 % (-30 to +50 °C) to WISG to blackbody...