“…Starting from the geometrical acoustics, ray theory limit, it is well known that we must add the respective zonal, meridional and vertical mean wind components (u,v,w) as presented in Jones (1969), in Thompson (1972) and in vector form in Landau and Lifshits (1987) to the wave normal path, group velocity equations with group velocity speeds {c gx ,c gy ,c gz } in the {x,y,z}, Cartesian coordinate system which for a perfectly stratified, steady-state atmosphere and for almost-plane waves (b 51) with no changes in the wave normal propagation heading, f, reduces to (Milne, 1921;Groves, 1955;Lindsay, 1960;Thompson, 1972;ReVelle, 2010ReVelle, , 2004:…”