Parameter Inversions of Multi-Layer Media of Mars Polar Region with Validation of SHARAD Data

Chuan Liu,Ya-Qiu Jin

doi:10.4236/ijaa.2019.93024

Abstract

HF (high frequency) radar sounder technology has been developed for several missions of Mars surface/subsurface exploration. This paper presents a model of rough surface and stratified sub-surfaces to describe the multi-layer structure of Mars polar deposits. Based on numerical simulation of radar echoes from rough surface/stratified interfaces, an inversion approach is developed to obtain the parameters of Polar Layered Deposits, i.e. layers thickness and dielectric constants. As a validation example, the SHARAD radar sounder data of the Promethei Lingula of Mars South Polar region is adopted for parameters inversion. The result of stratification is also analyzed and compared with the optical photo of the deep cliff of Chasma Australe canyon. Dielectric inversions show that the deposit media are not uniform, and the dielectric constants of the Promethei Lingula surfaces are large, and become reduced around the depth of 20 m - 30 m, below where most of the deposits are nearly pure ice, except a few thin layers with a lot of dust.

Highlights

The physical properties of Mars polar deposits have been studied for several decades
Based on numerical simulations of the radar sounder echoes from the one-layer model with rough surface/subsurface media, Ye and Jin [11] found that under the Kirchhoff approximation with a mean zero slope, the received echo at nadir direction preserves the functional dependence of the surface reflectivity
This paper presents a model of rough surface and stratified interfaces to describe the multi-layer structure of Mars Polar Layered Deposit

Summary

Introduction

The physical properties of Mars polar deposits have been studied for several decades. Based on numerical simulations of the radar sounder echoes from the one-layer model with rough surface/subsurface media, Ye and Jin [11] found that under the Kirchhoff approximation with a mean zero slope, the received echo at nadir direction preserves the functional dependence of the surface reflectivity. It leads to the inversion of the surface dielectric permittivity derived from the ratios of the received echo powers and the medium reflectivity. Inversions are applied to SHARAD data on Promethei Lingula of Mars SPLD

Model of the Stratified Media and Inversion of Dielectric Constants

Findings

Conclusions