A sun–sky radiometer is a narrow band filter photometer able to perform measurements of direct solar and diffuse sky irradiances at some selected wavelengths (315, 400, 500, 675, 870, 940 and 1020 nm for model POM01, and 315, 340, 380, 400, 500, 675, 870, 940, 1020, 1675, 2200 nm for model POM02)and at several scattering angles in the Almucantar and Principal plane geometries. Measurements of direct irradiance are taken every 1 minute, and of diffuse sky irradiances every 10 minutes.
The optical system of the instrument is composed by a collimator tube 30 cm long; a convex lens is located at 70 mm from the sensor that is a silicon photodiode used for measuring both direct and diffuse solar flux radiation. A rotating filter wheel located between the lens and the sensor, holds the interferential filters for the selection of the wavelengths. The band width of each filter is about 10 nm. The optical view angle of the instrument is 1°. The optical system is equipped with an automatic solar tracker allowing to centre the solar disk, and to automatically follow its movement during the day. Both filters and sensor are kept at a constant temperature (user definable between 0° to 40°) by a worming thermostat.
The optical system is connected to the head of the instrument where two stepping motors, model VEXA 5-PHASE PH 564-N, control the azimuthal and zenithal movements.The instrument is equipped with a rain sensor that, connected with the stepping motors, allow to park the optical system in a position that prevent contamination from rain.
The PREDE-POM 01 installed at the BAQUNIN supersite is part of the International network ESR/SKYNET.
Campanelli at al., Monitoring of Eyjafjallajökull volcanic aerosol by the new European Skynet Radiometers (ESR) network (2012), Atmos.Environ., Volume 48, March 2012, doi:10.1016/j.atmosenv.2011.09.070
PI: Monica Campanelli, <a href=”mailto:email@example.com” target=”_blank” rel=”noopener noreferrer”>firstname.lastname@example.org</a>