The third SeaWiFS Intercalibration Round-Robin Experiment (SIRREX-3) , 19-30 September 1994

This report presents results of the third Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Intercalibration Round-Robin Experiment (SIRREX-3). Specral irradiances of FEL lamps belonging to each participant were intercompared by reference to the National Institute of Standards & Technology (NIST) scale of spectral irradiance using secondary standard lamps F268, F269 and F182, with a Type A uncertainty between 1.1-1.5%. This level of uncertainty was achieved despite difficulties with lamp F269. with two exceptions, spectral radiance values of integrating sphere sources were measured during SIRREX-3 with uncertainties in temporal stability of less than 0.3% and absolute uncertainties of 1.5-2.0%. Plaque reflectances were intercompared with an uncertainty of about 1-2%, but the absolute uncertainty is undefined. -from Authors