Glossary of Solar Radiation Resource Terms

Other relevant glossaries


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Radiation - in the context of the RReDC, synonymous with electromagnetic radiation, or the energy produced by an oscillating electrical (and magnetic) field, transmitted by photons. See Electromagnetic Spectrum.


Radiometer - an instrument that measures radiance, or the radiation emitted by an object.


Radiosonde - an instrument package that moves through the atmosphere, usually attached to a balloon, and transmits data over a radio frequency.


Raman Scattering - Sir Chandrasekhara Venkata Raman (1888-1970) was the Indian physicist who discovered that when a beam of light passes through a liquid or a gas, it is scattered and the frequency of some of the scattered light is changed. The amount of change is a function of the scattering particles and the wavelengths of light.


Random Error - the difference between the actual and the desired quantity that varies randomly; that is, if a probability distribution of differences is produced, it is the Gaussian error function.


Rayleigh Scattering - the scattering of solar radiation by (mathematically spherical) particles in the atmosphere which are much smaller than the wavelength of light, analyzed by Lord Rayleigh. Rayleigh scattering explains the blue sky.


RCC - Radiometer Calibration & Characterization (RCC) software is used to automate the BORCAL process. The RCC controls all data acquisition from the reference radiometers and those under calbration, displays several color-coded fields representing the present sky condition and instrument performance, builds an instrument calibration database, and generates the final calibration report.


Renewable Energy - there is no formal definition for this term. Typical usage defines it as any energy source that is replenished at least as fast as it is used. Standard examples are solar, wind, hydroelectric, and biomass products.


Receiver - a device that receives solar energy and converts it to useful energy forms. The following figure from Shining On illustrates several types of receivers.


Reflectance - the fraction or percent of a particular frequency or wavelength of electromagnetic radiation that is reflected from the surface of a substance without being absorbed or transmitted.


Refraction - the bending of electromagnetic radiation by its passage through a medium of a high refractive index. Light is refracted by passing through a lens, water, or the atmosphere.


Relative Humidity - the amount of water vapor in the air expressed as the ratio between the measured amount and the maximum possible amount (the saturation point at which water condenses as dew).


Remote Sensing - the determination of a quantity by detecting it from a distance. A common application of remote sensing is the use of satellite-borne instruments to determine the location and amount of resources on the surface of the Earth.


Re-radiation - the re-emission of electromagnetic radiation that had been previously absorbed by a substance.


Rotating Shadow Band Radiometer - an instrument that determines total solar radiation and diffuse sky radiation by periodically shading the total sky sensor from the sun with a rotating shadow band. Below is a picture of a rotating shadow band radiometer at the Solar Radiation Research Laboratory. The curved black shadowband at the right of the instrument is at rest; once every minute, it rotates 180° to obscure the sun for a few seconds, then returns to its resting position.

   


The following links allow you to move to the words beginning with that letter.

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