Inclination Dependence Of Pyranometer Sensitivity

The inclination dependence of the sensitivity of Eppley Model 8-48 pyranometers has been measured indoor tests conducted at levels of illumination corresponding to roughly 500 and 1000 w.m. The sensitivity is found to decrease as the pyranometer is tilted from the horizontal, the magnitude of the decrease depending on the level of illumination as well as the angle of inclination. Outdoor comparisons of Eppley Model 8-48 and Model PSP pyranometers, although less well controlled, generally confirm the measured inclination dependence.