Abstract:
In this paper, an efficient scheme for extracting the complex bottom reflection coefficient (phase and amplitude) in a shallow-water waveguide by using the Wentzel--Kramers--Brillouin (WKB) modal condition is proposed. The input data are the measured modal wave number (k[inf m]) and the modal attenuation ((beta)[inf m]). The main advantages of this scheme are (1) it is efficient, because there are no replica calculations as in the conventional matched-field processing (MFP) scheme; (2) the inverted error induced by the ``noise'' of the contaminated data can be estimated analytically; and (3) the impact of the environmental (SSP) mismatch can also be estimated analytically. Numerical simulations illustrate that the proposed scheme works well in different scenarios of shallow-water waveguides. [Work supported by ONR and NOAA.]