ABSTRACT
Michalsky, Berndt, and Schuster (1986) built a microprocessor-controlled version of the rotating shadowband radiometer that recorded four measurements from the photodiode pyranometer for each rotation of the stepper motor-driven band. The measurements are made with the band in the nadir position to measure unobstructed global horizontal irradiance, blocking the sun to measure the diffuse horizontal irradiance, and with the band offset symmetrically slightly before and slightly after the sun-blocking position to estimate the excess diffuse sky radiation blocked by the band during the blocked-sun measurement. The blocked-sun position of the band prevents the direct sun from reaching the receiver but also blocks circumsolar diffuse skylight. An estimate of this correction is calculated using the two side-band measurements.
