IR02 is a pyrgeometer suitable for longwave irradiance measurements in meteorological applications. The instrument can be heated, which improves measurement accuracy as it prevents dew deposition on its window. Because of features like this, IR02 is popular and often used in agricultural networks.

IR02 measures the longwave or far-infrared radiation received by a plane surface, in W/m², from a field of view angle of approximately 150 ^o. Longwave radiation is the part of radiation that is not emitted by the sun. The actual field of view angle of IR02 is not the ideal 180^o. The reduction of this field of view makes it possible to offer an instrument at an attractive price level, while the accuracy loss is relatively small. IR02 has a window with a cut-on at 4.5 x 10^-6 m, making it suitable for day- and night observations.

IR02 pyrgeometer has a high sensitivity. With sufficient input signal a typical datalogger no longer contributes to the uncertainty of the measurement. IR02 houses an on-board heater. Heating prevents condensation of water on the pyrgeometer window which, when occurring, leads to very large measurement errors.

Using IR02 is easy. It can be connected directly to commonly used data logging systems. The irradiance in W/m² is calculated by dividing the IR02 output, a small voltage, by the sensitivity and by taking into account the irradiated heat by the sensor itself (Stefan-Boltzmann law). The sensitivity is provided with IR02 on its product certificate.

_{Click on drawing in Gallery for IR02 dimensions: Standard cable length is 5 m. All dimensions are in mm.}