A large data base comprising SEASAT A satellite scatterometer measurements and quasi-concurrent high quality sea wind data, as represented by Britt and Schroeder (1984) in the form of a multivariate regression, has been used to tune the overall magnitude of the assumed sea spectrum by inverting the two scale scattering theory. Scattering coefficient values computed for the derived spectrum have been compared with those computed for the spectrum suggested by earlier authors, and an improvement is found in the surface wind-scattering coefficient relationship as verified by comparison with the independent AAFE RADSCAT data set.