Normal‐mode description of reverberation with a finite area bottom patch average

A normal‐mode reverberation model is presented that includes the effects of modal interference among spatially correlated fields scattered within a patch of (nearby) bottom locations. At each frequency the integrated scattered field from a bottom patch as a function of patch size is calculated from an explicit normal‐mode expression. The time integrated reverberation level at each frequency is computed by squaring this contribution from each patch and summing over bottom patches. As a function of source/receiver separation, the time integrated reverberation levels computed with the finite patch description oscillate about a mean that is consistently lower than the levels obtained in the zero patch area limit. Results from a study of the dependence of the level differences and oscillation magnitudes on environment, frequency and patch area are presented. [Work supported by the Advanced Surveillance and Prediction System (ASAPS) Program of the Space and Naval Warfare Systems Command (SPAWAR, PMW 183‐32).]