“…W (0, d , jω ) is the attenuation function along the mixed propagation path. For a mixed propagation path, two different attenuation functions are given by Wait [1974] and Wait and Walters [1963a, 1963b]: where W 1 (0, d , jω ) and W 2 (0, d , jω ) are the attenuation functions for the first and second sections, respectively: …”