Specifications
IR20 & IR20WS
| Measurand | longwave radiation |
| Optional measurand | sky temperature, surface temperature |
| Sensitivity (nominal) | 17 x 10⁻⁶ V/(W/m²) |
| Spectral range IR20 | 4.5 to 40 x 10⁻⁶ m (nominal) |
| Spectral range IR20WS | 1.0 to 50 x 10⁻⁶ m |
| IR20WS restrictions for use | only in the absence of solar radiation |
| Field of view angle | 180 ° |
| Response time (95 %) | 3 s |
| Rated operating temperature range | -40 to +80 °C |
| Temperature dependence | < ± 0.4 % (-30 to +50 °C) |
| Calibration traceability | to WISG |
| Optional traceability | to blackbody (ITS-90) |
| Temperature sensor | 10 kΩ thermistor |
| Heater | 12 VDC, 1.5 W |
| Standard cable length | 5 m |
Options
- longer cable, in multiples of 5 metres
- blackbody calibration (ITS-90)
- VU01 ventilation unit is designed for use with IR20 / IR20WS pyrgeometer
Downloads
(PDF, 308.13 KB)
(PDF, 1.81 MB)
(PDF, 272.8 KB)
IR20 and IR20WS research grade pyrgeometers
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 under conditions during night-time, when solar radiation is absent.
IR20 Pyrgeometer benefits
- breakthrough pricing for a pyrgeometer of this performance level as a result of Hukseflux’ technological innovation.
- correction of temperature dependence by use of the measurement function. This is far more accurate than temperature compensation in the instrument, especially at very low and high temperatures. Every pyrgeometer is supplied with temperature coefficients to enter into the equation.
- high sensitivity. With sufficient input signal a typical datalogger no longer significantly contributes to the uncertainty of the measurement.
- low thermal-resistance of the sensor. Competing designs need a significant correction for the difference in temperature between pyrgeometer body and sensor surface. For IR20 this is not needed.
- fast response time (3 s). A low response time is a benefit for measurements on moving platforms such as aircraft and buoys.
- on-board heater. Heating prevents condensation of water on the pyrgeometer dome which, when occurring, leads to very large measurement errors.
- instrument cut-on wavelength (5 %) and the two 50 % transmission points are displayed on the product certificate for individual sensors.
Suggested use
- climatological networks
- extreme climates (polar / tropical)
- moving platforms (aircraft, buoys)
- uncertainty assessment (IR20 + IR20WS)
- calibration reference (IR20WS)
Areas of Application
PMF01
IR20 & IR20WS pyrgeometer
- breakthrough pricing for a pyrgeometer
- correction of temperature dependence by use of the measurement function
- high sensitivity
- fast response time (3 s)
- on-board heater
