Numerical Simulation and Analysis of the Spiky Sea Clutter from the Sea Surface With Breaking Waves

摘要

This paper presents a feasible and efficient scattering model of the time-varying complex sea surface process to the field of sea spike modeling. To describe the phenomena of sea spikes as well as the “super events” from realistic sea clutter, wedges are posited on the two-scale sea surface to provide an approximate simulation of the breaking waves. The scattering of the wedge and multiple reflections that occur from the sea and wedges are considered in ray tracing for a large HH/VV ratio. With this technique, we obtained the time sequence of the time-varying sea surface and identified the spiking events in the background. Sea clutter properties with breaking waves are compared with that of the sea. Results indicate that spiking events are more likely to occur in the sea with breaking waves. The probability distribution function (PDF) curve of the sea surface with breaking waves has a heavy trail in the large amplitude region. The decorrelation time of the sea with breaking waves is significantly longer compared with the sea without breaking waves, particularly, for HH polarization. The spike properties of sea clutter in different wind speeds and resolutions are also investigated. Results show that spike events are more likely to happen under a high sea state and radar resolution. The Doppler spectrum of the sea with breaking waves showed remarkable improvement for both polarizations. All simulation results indicate that the proposed scattering model effectively stimulates sea clutter with a low grazing incident angle and explains the physical mechanism of the sea spikes.