Estimation of decorrelation rates of scattering from a heterogeneous seafloor.

In pulse-echo sonar, the temporal coherence of echoes from the seafloor can provide an acoustic means to observe subtle long- or short-term changes in the seabed. Measurements of scattering from a seabed composed of sand, clay, and gravel in the Gulf of Maine were made over a period of 8 months. A parametric estimation approach, using a piecewise exponential function, is described and applied to the data to more accurately estimate nonstationary decorrelation rates. This approach may aid in quantifying and describing the rate of change in seafloors with mixed composition and in complex ocean environments with multiple forcing mechanisms.