A reanalysis of equivalent-width data for 19 northern supergiants considered in previous chemical composition studies is conducted with improved techniques and atomic data in order to place all supergiant abundances on the same scale. Although surface gravities and surface temperatures show only minor changes with respect to previously obtained values, microturbulent velocities are increased by an average of 50%, leading to a desaturation of the lines and a consequent decrease in derived abundances. The solar-neighborhood supergiants are thus brought to within 0.1 dex of the sun and local F-type dwarfs, in view of a decrease in Fe/H abundance ratio values of 0.2 dex. It is also shown that while most equivalent widths are on the same scale those of the southern stars are systematically high with respect to the remaining values, requiring the exclusion of nine stars from consideration in local and galactic metallicity discussions.
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R. E. Luck (1982) studied this question.