Solar radiometers are based on the conversion of radiation to thermal energy which is measured by an electrically calibrated thermal flux meter. Cavities are used to improve the absorption of solar radiation.
Therefore, there is no way for a direct measurement of solar radiation, and it is always estimated by an indirect or a two-step method, based well on thermal, or well on photonic effects. In many cases, thermal detectors of solar radiation have also been used as detectors of infrared radiation (and vice versa).
This process is experimental and the keywords may be updated as the learning algorithm improves. The term solar radiometry is generally used to refer to measurements of the “solar constant”, the total solar irradiance (TSI), integrated over all wavelengths and reduced to the mean Sun-Earth distance, 1 ua; it is an observation of the Sun as a star.
Policies and ethics An instrument able to measure electromagnetic radiation, in its different forms and spectral ranges, is called a radiometer. This chapter focuses on the radiometers used for sensing solar radiation and on the measurements of different components and types of...
Both Angström and ACR pyrheliometers are currently the primary reference instruments for the magnitude of solar irradiance in many national radiometric laboratories. Due to the key importance of these sensors, further details are later given in other sections of this chapter. Photoelectric devices.
The solar radiation may be characterized by the measured solar irradiance (power per area at a given moment) (or radiation) and by the solar insolation (the energy per area delivered over a specified time period). The solar radiance is an instantaneous power density in units of kW/m 2.