Nonlinear Dynamics of Sea Clutter

We review experimental evidence for the nonlinearity of sea clutter and the role of the z-parameter or Mann-Whitney rank-sum statistic in quantifying this nonlinear behavior in the context of a hybrid AM/FM model for sea clutter, viewed as a cyclostationary process. An independent theoretical derivation of the stochastic dynamics of radar scattering in a sea clutter environment, in terms of a pair of coupled stochastic differential equations for the received envelope and radar cross-section (RCS), enables the identification of nonlinearity in terms of the shape parameter for the RCS. We are led to conclude that, from both experimental and theoretical points of view, thedynamics of sea clutter are nonlinear with a consistent degree of nonlinearity that is determined by the sea state