A comparison of observed and model-predicted atmospheric perturbations on target radiances measured by ERTS: Part I-Observed data and analysis

Two targets of measured, constant reflectivity in the area of San Francisco, California are studied. The first standard, a waste (carbon black) treatment pond at an oil refinery near Suisan Bay, having an area of approximately 0.3 square miles, (or 215 pixels), and bandpass reflectances of <0.5% in all four bands, is assumed to have a zero contribution to the radiance recorded by ERTS. The radiance observed then arises entirely from atmospheric scattering. The variation in these radiance values as a function of solar zenith angle has been analyzed. A second target, a concrete parking apron for aircraft at Moffett Field, California, assuming that it remains dry during the period of study has constant reflectances of 27.8, 31.0, 30.0, and 32.3 percent bandpass reflectances in four MSS equivalent channels. Using these values, the radiance observed by ERTS may be corrected for the atmospheric contribution, and thus values for the radiance from the target may be calculated. These values were studied as a function of solar zenith angle.