Response to “Comment on ‘Anomalous reflection from a two-layered marine sediment’ ” [J. Acoust. Soc. Am. 156, 1524–1527 (2024)]

In their Comment,¹ the authors consider a similar, two-layer problem to that addressed by Buckingham² (referred to below as MJB) but instead of an inverse-square sound speed profile in the upper layer, they treat the case of an n²-linear profile or as it is sometimes called an Airy medium. Their results for the modulus of the plane wave reflection coefficient, |R|, are almost identical to those of MJB, compare, for example, the red curve in their Fig. 3(a) with the green curve in Fig. 8 in MJB, except that the spikes of acoustic glint are absent in the former.

In their concluding remarks, the authors graciously emphasize that they are not claiming that the computations in MJB are incorrect, but rather that the presence of the glint is very sensitive to the shape of the sound speed profile in the top layer of the sediment. This conclusion is consistent with the observation in MJB that the angular width of most of the lines of glint is extremely narrow, often just a few hundredths of a degree or less. This suggests that the existence of the glint is critically dependent on the detailed nature of the sound speed profile. The authors, in their Comment, suggest that the glint could be associated with a convex profile (inverse-square) as opposed to concave (n²-linear), which seems plausible.