Signal structure outside the underwater sound channel: Wave effects

Potentialities of ray and wave theories are investigated in the context of estimating the duration of broadband signals under the condition that the c orrespondent points are located outside an underwater sound channel with pr ominent boundaries formed by high vertical gradients of sound velocity las it is the case in the northwestern Pacific). It is shown that the ray theor y may cause considerable errors (up to 0.45 s at a distance of 100 km), whi le the wave theory appropriately describes all features of measured signals .