Broadband visible/near infrared and far infrared radiometers (henceforth referred to as "visible" and "infrared") are operated at Chilbolton Facility for Atmospheric and Radio Research (CFARR).
The radiometers point vertically and collect downwelling flux by measuring the whole sky irradiance integrated over a range of wavelengths. The visible band pyranometer measures solar irradiance over the wavelength range 305-2800nm; the infrared band pyrgeometer is blind to incident solar radiation but measures re-emitted longer wavelength radiation over the wavelength range 4.5-42µm. Both instruments operate automatically and continuously.
The instruments are sent for factory re-calibration every 2 years and were unavailable over the following periods:
In addition no data are available from either instrument during the period 05/10/2007 to 21/10/2007 inclusive.