Marine Acoustics: Direct and Inverse Problems

In this section we continue to restrict our attention to constant depth oceans with completely reflecting seabottoms. However, in the present example we consider the case where there is a seamount on the ocean floor. We wish to reconstruct the seamount using far-field data. To this end we generate an acoustic field using a point source at a given location, say
. The acoustic pressure then satisfies
and the outgoing radiation condition. Here we assume that
, and k 2 is not an eigenvalue of the exterior boundary problem.
D represents the seamount, and
is the surface of the seamount, which has a parameterization
here a is some positive constant where we assume that the seabottom is flat for r > a.
For a constant depth ocean without a seamount, the solution to (3.95) (3.98) is the Helmholte-Green function in
, which has the form
where the g(z) are the point sources
The solution of problem (3.95) (3.98) can be represented as
for
; here p sc(
) is the unique solution of the integral equation
and
The inverse problem is the following: Given p(
) for all
? ?, := {( r, ?, z) : z = d = constant} and
0, determine the seamount M [8].
We assume that both T 1 (the receiving plane) and T 2 (the source location plane)...