Numerical Simulation of VHF Radar Echoes of Sea Ice Based on Mueller Matrix Solution

Abstract

Based on the time domain Mueller matrix solution, a method for VHF (very high frequency, 30-300MHz) radar pulse penetration on sea ice, programming by Visual C#, is developed. The polarimetric radar pulse echoes contain echoes from top and bottom interfaces, air-bubble's volumetric scattering and their multi- interactions. By changing model parameters including the layer thickness, salinity, dielectric constant and interfacial roughness, the radar pulse echoes on sea ice are numerically simulated to verify the feasibility of this method. The results demonstrate that the model can be used to explore sea ice, of which rich information such as depth and other structure properties can be revealed. Index Terms - Scattering model; Mueller matrix solution; Sea ice layer exploration; Numerical simulation. information of sea ice layer and beneath information. The VHF radar, which is not sensitive to clouds and sun light, can provide high resolution remote sensing images in all weather. The VHF radar is sensitive to roughness and salinity of sea ice, which is valid to identify different types and classify characteristics. Therefore, in order to monitor sea ice change dynamically and provide disaster warnings, we must use Very High Frequency (VHF, 100-300 MHz ) radar. 2. Sea ice simulation model and theory This paper proposes a method for VHF radar to detect the structure of sea ice layer. Sea ice is a mixture of pure ice, non- spherical salt solution impurities and air bubbles with random distribution. Dielectric properties of salt solution impurities and air bubbles affect the dielectric properties of sea ice greatly (3), and especially increase the scattering properties of sea ice. In this paper, the sea ice is regarded as a lossy dielectric layer, which has random rough surface and bottom. Mixture of pure ice and salt solution impurity is the background medium, while air bubbles with random distribution and orientation in the sea ice layer are scatterers. We constructed the Mueller matrix solution of the model from vector radiative transfer (VRT) equation. By changing the dielectric parameters of sea ice, we obtain the numerical simulation radar echoes. VHF radar can detect differences of radar echoes under different conditions of sea ice, while the layer structure and physical characteristics can be revealed.