A Creamer Nonlinear Ocean Surface Doppler Spectrum Simulation of a Fine Physical Model Covered by Oil Film

Abstract

In this paper, the modeling of the Doppler spectrum from a time-evolving Creamer nonlinear ocean covered by oil film is presented based on a refined physical surface spectrum model of damping due to oil. The influence of oil film on the ocean surface spectrum and geometrical structure is examined briefly in the present study. On this basis, the Doppler spectra of the backscattered echo from the time-evolving Creamer nonlinear contaminated ocean are investigated in detail based on the iterative physical optics method. The Doppler spectra of the backscattered echo from clean and contaminated ocean are compared for the linear and Creamer nonlinear surfaces at various incident angles firstly. Due to the nonlinear hydrodynamics, the Doppler spectral widths of the Creamer nonlinear ocean for both clean and contaminated ocean are broader than the corresponding linear ocean counterparts as the incident angle increases. It manifests the necessity of using Creamer nonlinear model to simulate the contaminated ocean surface. Then, the simulations focus on the Doppler spectra of the contaminated rough ocean surface with different oil parameters. Simulation results show that the Doppler spectrum signatures including Doppler shift and spectral widths of the backscattered echo are affected by oil film, which are qualitatively consistent with wavetank or open ocean measurements. Furthermore, it indicates that Doppler spectrum technique is a promising tool for remote sensing of oil films floating on ocean surface.