Spring and Fall Measurements of European Very Low Altitude Volume Scattering Coefficients

This report presents measurements of atmospheric volume scattering coefficients collected during twenty-five low altitude flights made mostly during the Spring and Fall seasons of 1976 and 1977 at four different European locations. The measurements were conducted during an instrumented aircraft's final approach and landing at its staging airbase. The measurements were made using a pseudo-photopic spectral response and thus are suitable for comparison with data associated with standard visual determinations of airfield visibility. The data illustrate that in twenty-two of twenty-five cases, there was little or no significant variation in the value of scattering coefficient as the aircraft approached the surface from an altitude of several hundred meters. (Author)