Lateral velocity variation

Having approximated the square root by a polynomial ratio, Table .3 or Table .4 can be inverse transformed from the horizontal wavenumber domain k_x to the horizontal space domain x by substituting $\ (ik_x )^2 = \partial^2 / \partial x^2$.As before, the result has a wide range of validity for v = v(x,z) even though the derivation would not seem to permit this.