Abstract: The low background aerosol loadings prevailing over much of the Australian continent necessitate careful attention to the calibration of sun photometers. The validity of such calibrations can only be assessed objectively ...

Abstract: In Lauder, Central Otago, New Zealand, two all-sky imaging systems have been in operation for more than 1 yr, measuring the total, opaque, and thin cloud fraction, as well as indicating whether the sun is obscured by clouds. ...